diff --git a/projects/element-ng/autocomplete/si-autocomplete.directive.spec.ts b/projects/element-ng/autocomplete/si-autocomplete.directive.spec.ts
index 073337caa..d9b6fd918 100644
--- a/projects/element-ng/autocomplete/si-autocomplete.directive.spec.ts
+++ b/projects/element-ng/autocomplete/si-autocomplete.directive.spec.ts
@@ -57,6 +57,7 @@ describe('SiAutocompleteDirective', () => {
 
   afterEach(() => {
     vi.useRealTimers();
+    vi.restoreAllMocks();
   });
 
   it('should be navigable', async () => {
diff --git a/projects/element-ng/circle-status/si-circle-status.component.spec.ts b/projects/element-ng/circle-status/si-circle-status.component.spec.ts
index d958c488a..5d51ee1df 100644
--- a/projects/element-ng/circle-status/si-circle-status.component.spec.ts
+++ b/projects/element-ng/circle-status/si-circle-status.component.spec.ts
@@ -40,6 +40,10 @@ describe('SiCircleStatusComponent', () => {
     element = fixture.nativeElement;
   });
 
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   it('should not set icon class, if no icon is configured', async () => {
     icon.set(undefined);
     await fixture.whenStable();
diff --git a/projects/element-ng/column-selection-dialog/si-column-selection-dialog.component.spec.ts b/projects/element-ng/column-selection-dialog/si-column-selection-dialog.component.spec.ts
index d82dea3a9..8cff9e789 100644
--- a/projects/element-ng/column-selection-dialog/si-column-selection-dialog.component.spec.ts
+++ b/projects/element-ng/column-selection-dialog/si-column-selection-dialog.component.spec.ts
@@ -5,6 +5,7 @@
 import { inputBinding, signal, twoWayBinding, WritableSignal } from '@angular/core';
 import { ComponentFixture, TestBed } from '@angular/core/testing';
 import { ModalRef } from '@siemens/element-ng/modal';
+import { afterEach } from 'vitest';
 
 import { SiColumnSelectionDialogComponent } from './si-column-selection-dialog.component';
 import { Column } from './si-column-selection-dialog.types';
@@ -86,6 +87,8 @@ describe('ColumnDialogComponent', () => {
     element = fixture.nativeElement;
   });
 
+  afterEach(() => vi.useRealTimers());
+
   it('should create', async () => {
     columns.set(cloneData());
     await fixture.whenStable();
@@ -257,20 +260,21 @@ describe('ColumnDialogComponent', () => {
 
   it('should toggle edit mode with keyboard', async () => {
     const spy = vi.spyOn(modalRef.hidden, 'next');
+    vi.useFakeTimers();
     columns.set(cloneData());
-    fixture.autoDetectChanges();
+    await fixture.whenStable();
     document
       .querySelector<HTMLSpanElement>('si-column-selection-editor')!
       .dispatchEvent(new KeyboardEvent('keydown', { key: 'Enter' }));
+    vi.advanceTimersToNextFrame();
     await fixture.whenStable();
     expect(spy).not.toHaveBeenCalled();
     const inputField = document.querySelector<HTMLInputElement>(
       'si-column-selection-editor input.form-control'
     )!;
     expect(inputField).toBeInTheDocument();
-    // Wait for setTimeout in startEdit() to complete
-    await new Promise(resolve => setTimeout(resolve, 100));
     inputField.dispatchEvent(new KeyboardEvent('keydown', { key: 'Enter', bubbles: true }));
+    vi.advanceTimersToNextFrame();
     await fixture.whenStable();
     expect(
       document.querySelector<HTMLInputElement>('si-column-selection-editor input.form-control')
diff --git a/projects/element-ng/content-action-bar/si-content-action-bar.component.spec.ts b/projects/element-ng/content-action-bar/si-content-action-bar.component.spec.ts
index 89dad3297..e203c1287 100644
--- a/projects/element-ng/content-action-bar/si-content-action-bar.component.spec.ts
+++ b/projects/element-ng/content-action-bar/si-content-action-bar.component.spec.ts
@@ -116,9 +116,21 @@ describe('SiContentActionBarComponent', () => {
     // cannot use jasmine.clock here
     await new Promise(resolve => setTimeout(resolve, 50));
     expect(await harness.isPrimaryExpanded()).toBe(false);
-    await harness.togglePrimary();
-    await fixture.whenStable();
-    expect(await harness.isPrimaryExpanded()).toBe(true);
+
+    // Click the primary toggle button directly instead of going through harness.togglePrimary()
+    // to avoid CDK harness stability checks that can hang due to ResizeObserver + auditTime(0) feedback loop.
+    const toggleButton = fixture.nativeElement.querySelector(
+      'button[si-content-action-bar-toggle]:not(.cdk-menu-trigger)'
+    ) as HTMLElement;
+    toggleButton.click();
+    fixture.detectChanges();
+    // Wait for the setTimeout in expand() and ResizeObserver cycle to settle
+    await new Promise(resolve => setTimeout(resolve, 100));
+    fixture.detectChanges();
+    const listItem = fixture.nativeElement.querySelector(
+      '[siAutoCollapsableListItem]'
+    ) as HTMLElement;
+    expect(getComputedStyle(listItem).visibility).toBe('visible');
   });
 
   it('should disable menu item by disabled attribute', async () => {
diff --git a/projects/element-ng/datatable/si-datatable-interaction.directive.spec.ts b/projects/element-ng/datatable/si-datatable-interaction.directive.spec.ts
index 9c789a858..3972a123f 100644
--- a/projects/element-ng/datatable/si-datatable-interaction.directive.spec.ts
+++ b/projects/element-ng/datatable/si-datatable-interaction.directive.spec.ts
@@ -276,12 +276,14 @@ describe('SiDatatableInteractionDirective', () => {
 
       await refresh();
 
-      expect(wrapperComponent.selected).toContain({
-        id: 1,
-        firstname: 'First 1',
-        lastname: 'Last 1',
-        age: 50
-      });
+      expect(wrapperComponent.selected).toContainEqual(
+        expect.objectContaining({
+          id: 1,
+          firstname: 'First 1',
+          lastname: 'Last 1',
+          age: 50
+        })
+      );
     }
   });
 
@@ -317,12 +319,14 @@ describe('SiDatatableInteractionDirective', () => {
 
       await refresh();
 
-      expect(wrapperComponent.selected).toContain({
-        id: 1,
-        firstname: 'First 1',
-        lastname: 'Last 1',
-        age: 50
-      });
+      expect(wrapperComponent.selected).toContainEqual(
+        expect.objectContaining({
+          id: 1,
+          firstname: 'First 1',
+          lastname: 'Last 1',
+          age: 50
+        })
+      );
     }
   });
 });
diff --git a/projects/element-ng/date-range-filter/__screenshots__/si-date-range-calculation.service.spec.ts/SiDateRangeCalculationService-resolves-with-before-and-now-as-reference-1.png b/projects/element-ng/date-range-filter/__screenshots__/si-date-range-calculation.service.spec.ts/SiDateRangeCalculationService-resolves-with-before-and-now-as-reference-1.png
new file mode 100644
index 000000000..8d0764546
Binary files /dev/null and b/projects/element-ng/date-range-filter/__screenshots__/si-date-range-calculation.service.spec.ts/SiDateRangeCalculationService-resolves-with-before-and-now-as-reference-1.png differ
diff --git a/projects/element-ng/date-range-filter/si-date-range-calculation.service.spec.ts b/projects/element-ng/date-range-filter/si-date-range-calculation.service.spec.ts
index b3bbcb08e..a38de14ac 100644
--- a/projects/element-ng/date-range-filter/si-date-range-calculation.service.spec.ts
+++ b/projects/element-ng/date-range-filter/si-date-range-calculation.service.spec.ts
@@ -18,12 +18,17 @@ describe('SiDateRangeCalculationService', () => {
     expect(formatDate(d1, 'dateShort', 'en')).toEqual(formatDate(d2, 'dateShort', 'en'));
 
   beforeEach(() => {
+    vi.useFakeTimers();
     TestBed.configureTestingModule({
       providers: [SiDateRangeCalculationService]
     });
     service = TestBed.inject(SiDateRangeCalculationService);
   });
 
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   it('resolves with before', () => {
     const filter: DateRangeFilter = {
       point1: new Date('2023-07-15'),
diff --git a/projects/element-ng/datepicker/components/si-day-selection.component.spec.ts b/projects/element-ng/datepicker/components/si-day-selection.component.spec.ts
index f92a65406..3b39e6077 100644
--- a/projects/element-ng/datepicker/components/si-day-selection.component.spec.ts
+++ b/projects/element-ng/datepicker/components/si-day-selection.component.spec.ts
@@ -25,6 +25,10 @@ describe('SiDaySelectionComponent', () => {
   let fixture: ComponentFixture<TestComponent>;
   let helper: CalendarTestHelper;
 
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
   const selectDate = (date: number): void => {
     helper.clickEnabledCell(date.toString());
     fixture.detectChanges();
diff --git a/projects/element-ng/datepicker/si-calendar-button.component.spec.ts b/projects/element-ng/datepicker/si-calendar-button.component.spec.ts
index 3bcf772e6..7d0439c19 100644
--- a/projects/element-ng/datepicker/si-calendar-button.component.spec.ts
+++ b/projects/element-ng/datepicker/si-calendar-button.component.spec.ts
@@ -52,6 +52,10 @@ describe('SiCalendarButtonComponent', () => {
     fixture.detectChanges();
   });
 
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   it('should show datepicker overlay', async () => {
     calendarToggleButton().click();
     fixture.detectChanges();
@@ -72,11 +76,12 @@ describe('SiCalendarButtonComponent', () => {
     expect(spy).toHaveBeenCalled();
   });
 
-  it('should mark as touched if button is blurred', () => {
+  it('should mark as touched if button is blurred', async () => {
     const touchSpy = vi.spyOn(SiDatepickerDirective.prototype, 'touch');
     const button = calendarToggleButton();
     button.focus();
     button.blur();
+    await fixture.whenStable();
     expect(touchSpy).toHaveBeenCalled();
   });
 
diff --git a/projects/element-ng/datepicker/si-datepicker.component.spec.ts b/projects/element-ng/datepicker/si-datepicker.component.spec.ts
index a825fd620..c1287e7b7 100644
--- a/projects/element-ng/datepicker/si-datepicker.component.spec.ts
+++ b/projects/element-ng/datepicker/si-datepicker.component.spec.ts
@@ -64,6 +64,10 @@ describe('SiDatepickerComponent', () => {
     picker = await loader.getHarness(SiDatepickerComponentHarness);
   });
 
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   it('should includeTimeLabel matches enabledTimeText', async () => {
     const enabledTimeText = 'Consider Time';
     await updateConfig({ ...component.config(), enabledTimeText, showTime: true });
diff --git a/projects/element-ng/file-uploader/si-file-uploader.component.spec.ts b/projects/element-ng/file-uploader/si-file-uploader.component.spec.ts
index 2e187b750..de5872d27 100644
--- a/projects/element-ng/file-uploader/si-file-uploader.component.spec.ts
+++ b/projects/element-ng/file-uploader/si-file-uploader.component.spec.ts
@@ -108,6 +108,10 @@ describe('SiFileUploaderComponent', () => {
     element = fixture.nativeElement;
   });
 
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   const createFileList = (files: string[], type?: string[]): DataTransfer => {
     const dt = new DataTransfer();
     files.forEach((f, i) => dt.items.add(new File(['blub'], f, { type: type?.[i] })));
diff --git a/projects/element-ng/filtered-search/si-filtered-search.component.spec.ts b/projects/element-ng/filtered-search/si-filtered-search.component.spec.ts
index 913a70471..011a7e335 100644
--- a/projects/element-ng/filtered-search/si-filtered-search.component.spec.ts
+++ b/projects/element-ng/filtered-search/si-filtered-search.component.spec.ts
@@ -597,14 +597,13 @@ describe('SiFilteredSearchComponent', () => {
       await criterionValue?.sendKeys(TestKey.BACKSPACE);
 
       vi.useRealTimers();
-      // needed to avoid flaky test
       await new Promise(resolve => setTimeout(resolve, 0));
-      vi.useFakeTimers();
 
       await filteredSearch.freeTextSearch().then(async freeTextSearch => {
         await freeTextSearch.focus();
       });
-      await tick();
+      await new Promise(resolve => setTimeout(resolve, 100));
+      await fixture.whenStable();
 
       expect(await criterionValue?.isEditable()).toBeFalsy();
     });
@@ -2484,12 +2483,11 @@ describe('SiFilteredSearchComponent - With translation', () => {
     await tick();
     await value!.sendKeys('broken-format');
     vi.useRealTimers();
-    // needed to avoid flaky test
     await new Promise(resolve => setTimeout(resolve, 0));
-    vi.useFakeTimers();
     await value!.blur();
     await filteredSearch.clickSearchButton();
-    await tick();
+    await new Promise(resolve => setTimeout(resolve, 100));
+    await fixture.whenStable();
     expect(await value!.text()).toBe('Invalid Date');
     expect(spy).toHaveBeenCalledWith({
       criteria: [
diff --git a/projects/element-ng/form/si-form-container/si-form-container.component.spec.ts b/projects/element-ng/form/si-form-container/si-form-container.component.spec.ts
index 64d812e78..52b23f6ec 100644
--- a/projects/element-ng/form/si-form-container/si-form-container.component.spec.ts
+++ b/projects/element-ng/form/si-form-container/si-form-container.component.spec.ts
@@ -167,6 +167,7 @@ describe('SiFormContainerComponent', () => {
 
     afterEach(() => {
       vi.useRealTimers();
+      vi.restoreAllMocks();
     });
 
     it('should create', async () => {
diff --git a/projects/element-ng/formly/fields/number/si-formly-number.component.spec.ts b/projects/element-ng/formly/fields/number/si-formly-number.component.spec.ts
index 96e64ad8c..348d0f6ce 100644
--- a/projects/element-ng/formly/fields/number/si-formly-number.component.spec.ts
+++ b/projects/element-ng/formly/fields/number/si-formly-number.component.spec.ts
@@ -57,6 +57,10 @@ describe('formly number type', () => {
     fixture = TestBed.createComponent(FormlyTestComponent);
   });
 
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   it('should display the number input based on props provided', async () => {
     vi.useFakeTimers();
     const componentInstance = fixture.componentInstance;
diff --git a/projects/element-ng/landing-page/change-password/si-change-password.component.spec.ts b/projects/element-ng/landing-page/change-password/si-change-password.component.spec.ts
index ef80725b2..b7122ea70 100644
--- a/projects/element-ng/landing-page/change-password/si-change-password.component.spec.ts
+++ b/projects/element-ng/landing-page/change-password/si-change-password.component.spec.ts
@@ -21,16 +21,16 @@ describe('SiChangePasswordComponent', () => {
   let fixture: ComponentFixture<TestComponent>;
   let element: HTMLElement;
 
-  const passwordPolicyContent = signal<string>('Policy content');
-  const passwordStrength = signal<PasswordPolicy>(passwordStrengthValue);
-  const newPasswordLabel = signal('');
-  const confirmPasswordLabel = signal('');
-  const changeButtonLabel = signal('');
-  const backButtonLabel = signal('');
-  const disableChange = signal(false);
-  const passwordPolicyTitle = signal('');
-  const changePasswordRequested = vi.fn<(value: ChangePassword) => void>();
-  const back = vi.fn();
+  let passwordPolicyContent = signal<string>('Policy content');
+  let passwordStrength = signal<PasswordPolicy>(passwordStrengthValue);
+  let newPasswordLabel = signal('');
+  let confirmPasswordLabel = signal('');
+  let changeButtonLabel = signal('');
+  let backButtonLabel = signal('');
+  let disableChange = signal(false);
+  let passwordPolicyTitle = signal('');
+  let changePasswordRequested = vi.fn<(value: ChangePassword) => void>();
+  let back = vi.fn();
 
   const enterValue = (input: HTMLInputElement, value: string): void => {
     input.value = value;
@@ -38,6 +38,16 @@ describe('SiChangePasswordComponent', () => {
   };
 
   beforeEach(async () => {
+    passwordPolicyContent = signal<string>('Policy content');
+    passwordStrength = signal<PasswordPolicy>(passwordStrengthValue);
+    newPasswordLabel = signal('');
+    confirmPasswordLabel = signal('');
+    changeButtonLabel = signal('');
+    backButtonLabel = signal('');
+    disableChange = signal(false);
+    passwordPolicyTitle = signal('');
+    changePasswordRequested = vi.fn<(value: ChangePassword) => void>();
+    back = vi.fn();
     fixture = TestBed.createComponent(TestComponent, {
       bindings: [
         inputBinding('passwordPolicyContent', passwordPolicyContent),
diff --git a/projects/element-ng/landing-page/login-single-sign-on/si-login-single-sign-on.component.spec.ts b/projects/element-ng/landing-page/login-single-sign-on/si-login-single-sign-on.component.spec.ts
index 9075cbec6..555938ad6 100644
--- a/projects/element-ng/landing-page/login-single-sign-on/si-login-single-sign-on.component.spec.ts
+++ b/projects/element-ng/landing-page/login-single-sign-on/si-login-single-sign-on.component.spec.ts
@@ -10,11 +10,12 @@ import { SiLoginSingleSignOnComponent as TestComponent } from './si-login-single
 describe('SiLoginSingleSignOnComponent', () => {
   let fixture: ComponentFixture<TestComponent>;
   let element: HTMLElement;
-
-  const disableSso = signal(false);
-  const ssoEvent = vi.fn();
+  let disableSso = signal(false);
+  let ssoEvent = vi.fn();
 
   beforeEach(async () => {
+    disableSso = signal(false);
+    ssoEvent = vi.fn();
     fixture = TestBed.createComponent(TestComponent, {
       bindings: [inputBinding('disableSso', disableSso), outputBinding('ssoEvent', ssoEvent)]
     });
diff --git a/projects/element-ng/list-details/si-list-details.component.spec.ts b/projects/element-ng/list-details/si-list-details.component.spec.ts
index d8b146b0b..d77ec3a4f 100644
--- a/projects/element-ng/list-details/si-list-details.component.spec.ts
+++ b/projects/element-ng/list-details/si-list-details.component.spec.ts
@@ -85,10 +85,10 @@ describe('ListDetailsComponent', () => {
       const viewportHeight = window.innerHeight || document.documentElement.clientHeight;
       const bounding = elem.getBoundingClientRect();
       return (
-        bounding.top >= 0 &&
-        bounding.left >= 0 &&
-        bounding.bottom <= viewportHeight &&
-        bounding.right <= viewportWidth
+        Math.round(bounding.top) >= 0 &&
+        Math.round(bounding.left) >= 0 &&
+        Math.round(bounding.bottom) <= viewportHeight &&
+        Math.round(bounding.right) <= viewportWidth
       );
     };
     const drag = (
@@ -419,6 +419,10 @@ describe('ListDetailsComponent', () => {
       });
     });
 
+    afterEach(() => {
+      vi.restoreAllMocks();
+    });
+
     it('should navigate back and forward in mobile mode by clicking', async () => {
       vi.spyOn(ResizeObserverService.prototype, 'observe').mockReturnValue(
         of({ width: 100, height: 100 })
diff --git a/projects/element-ng/loading-spinner/si-loading-spinner.directive.spec.ts b/projects/element-ng/loading-spinner/si-loading-spinner.directive.spec.ts
index ae6c974c8..0b9fec5cf 100644
--- a/projects/element-ng/loading-spinner/si-loading-spinner.directive.spec.ts
+++ b/projects/element-ng/loading-spinner/si-loading-spinner.directive.spec.ts
@@ -69,6 +69,7 @@ describe('SiLoadingSpinnerDirective', () => {
   });
 
   it('should show and hide spinner', async () => {
+    await fixture.whenStable();
     await vi.advanceTimersByTimeAsync(initialDelay);
     await vi.advanceTimersByTimeAsync(initialDelay);
     expect(isLoading()).toBe(true);
diff --git a/projects/element-ng/number-input/si-number-input.component.spec.ts b/projects/element-ng/number-input/si-number-input.component.spec.ts
index da848b0bc..239ef2c4f 100644
--- a/projects/element-ng/number-input/si-number-input.component.spec.ts
+++ b/projects/element-ng/number-input/si-number-input.component.spec.ts
@@ -93,6 +93,10 @@ describe('SiNumberInputComponent', () => {
       element = fixture.nativeElement;
     });
 
+    afterEach(() => {
+      vi.useRealTimers();
+    });
+
     it('should support short press increments', async () => {
       value.set(50);
       await fixture.whenStable();
diff --git a/projects/element-ng/photo-upload/si-photo-upload.component.spec.ts b/projects/element-ng/photo-upload/si-photo-upload.component.spec.ts
index 7cd33b418..46f530479 100644
--- a/projects/element-ng/photo-upload/si-photo-upload.component.spec.ts
+++ b/projects/element-ng/photo-upload/si-photo-upload.component.spec.ts
@@ -16,22 +16,19 @@ describe(`SiPhotoUploadComponent`, () => {
   let componentRef: ComponentRef<SiPhotoUploadComponent>;
   let fixture: ComponentFixture<SiPhotoUploadComponent>;
   let callback: (e: any) => void;
-  let originalFileReader: typeof FileReader;
 
   const mockFileReader = (data: string): any => {
-    const readerSpy = {
-      addEventListener: vi.fn((event: string, cb: (e: any) => void) => (callback = cb)),
-      readAsDataURL: vi.fn(() => callback(data)),
-      result: data
-    };
-
-    originalFileReader = window.FileReader;
-    window.FileReader = class {
-      addEventListener = readerSpy.addEventListener;
-      readAsDataURL = readerSpy.readAsDataURL;
-      result = readerSpy.result;
-    } as any;
-    return readerSpy;
+    vi.spyOn(window, 'FileReader').mockImplementation(
+      class MockFileReader implements Partial<FileReader> {
+        addEventListener = (event: unknown, cb: (e: Event) => void): void => {
+          callback = cb;
+        };
+        readAsDataURL = (blob: Blob): void => {
+          callback(blob);
+        };
+        result = data;
+      } as typeof FileReader
+    );
   };
 
   const generateImage = (): File => {
@@ -60,11 +57,7 @@ describe(`SiPhotoUploadComponent`, () => {
     componentRef = fixture.componentRef;
   });
 
-  afterEach(() => {
-    if (originalFileReader) {
-      window.FileReader = originalFileReader;
-    }
-  });
+  afterEach(() => vi.resetAllMocks());
 
   it('should display placeholder', () => {
     componentRef.setInput('placeholderAltText', 'MX');
@@ -143,13 +136,12 @@ describe(`SiPhotoUploadComponent`, () => {
     await fixture.whenStable();
     const modal = document.querySelector('si-modal');
     expect(modal).toBeInTheDocument();
-    // cannot use vi.useFakeTimers here
-    await new Promise(resolve => setTimeout(resolve, 100)); // Allow cropping lib to process
-    expect(modal?.querySelector('img')).toBeInTheDocument();
+    // Wait for the cropping lib to render the image
+    await expect.poll(() => modal?.querySelector('img')).toBeTruthy();
   });
 
   it('should apply photo', async () => {
-    fixture.detectChanges();
+    await fixture.whenStable();
     const input = fixture.debugElement.query(By.css('input[type="file"]'));
     vi.spyOn(input.nativeElement, 'click').mockImplementation(() => {
       input.triggerEventHandler('change', {
@@ -162,17 +154,16 @@ describe(`SiPhotoUploadComponent`, () => {
 
     fixture.debugElement.query(By.css('button'))!.nativeElement.click();
 
-    fixture.detectChanges();
     await fixture.whenStable();
 
-    // cannot use vi.useFakeTimers here
-    await new Promise(resolve => setTimeout(resolve, 100)); // Allow cropping lib to process
+    // Wait for the cropping lib to render the image
+    await expect.poll(() => document.querySelector('si-modal img')).toBeTruthy();
 
     getButton(document.querySelector('si-modal')!, 'Apply').click();
-    fixture.detectChanges();
     await fixture.whenStable();
 
-    expect(fixture.debugElement.query(By.css('img'))!.attributes.src).toBeTruthy();
+    // Wait for the cropped image to be processed and rendered
+    await expect.poll(() => fixture.nativeElement.querySelector('img')?.src).toBeTruthy();
   });
 
   it('should apply photo without modal when disabledCropping = true', async () => {
diff --git a/projects/element-ng/pills-input/si-pills-input.component.spec.ts b/projects/element-ng/pills-input/si-pills-input.component.spec.ts
index 677de6bed..b4174d8f6 100644
--- a/projects/element-ng/pills-input/si-pills-input.component.spec.ts
+++ b/projects/element-ng/pills-input/si-pills-input.component.spec.ts
@@ -125,6 +125,10 @@ describe('SiPillsInputComponent', () => {
   });
 
   describe('with csv input handler', () => {
+    afterEach(() => {
+      vi.useRealTimers();
+    });
+
     it('should update on input with separator', async () => {
       csvInputElement.value = 'a';
       csvInputElement.dispatchEvent(new InputEvent('input'));
diff --git a/projects/element-ng/popover/si-popover.directive.spec.ts b/projects/element-ng/popover/si-popover.directive.spec.ts
index f79926817..4151bbc5c 100644
--- a/projects/element-ng/popover/si-popover.directive.spec.ts
+++ b/projects/element-ng/popover/si-popover.directive.spec.ts
@@ -50,6 +50,10 @@ describe('SiPopoverNextDirective', () => {
     wrapperComponent = fixture.componentInstance;
   });
 
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   it('should open/close on click', async () => {
     vi.useFakeTimers({ shouldAdvanceTime: true });
     fixture.detectChanges();
@@ -177,6 +181,10 @@ describe('with custom template', () => {
     fixture = TestBed.createComponent(CustomTemplateHostComponent);
   });
 
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   it('should focus on the first interactive element', async () => {
     vi.useFakeTimers({ shouldAdvanceTime: true });
     fixture.detectChanges();
diff --git a/projects/element-ng/resize-observer/resize-observer.service.spec.ts b/projects/element-ng/resize-observer/resize-observer.service.spec.ts
index 38adea52e..ba704de5a 100644
--- a/projects/element-ng/resize-observer/resize-observer.service.spec.ts
+++ b/projects/element-ng/resize-observer/resize-observer.service.spec.ts
@@ -23,12 +23,6 @@ class TestHostComponent {
   readonly height = signal(100);
 }
 
-// A timeout that works with `await`. We have to use `waitForAsync()``
-// in the tests below because `tick()` doesn't work because `ResizeObserver`
-// operates outside of the zone
-const timeout = async (ms: number): Promise<void> =>
-  new Promise(resolve => setTimeout(resolve, ms));
-
 describe('ResizeObserverService', () => {
   let fixture: ComponentFixture<TestHostComponent>;
   let component: TestHostComponent;
@@ -51,6 +45,7 @@ describe('ResizeObserverService', () => {
   };
 
   beforeEach(() => {
+    vi.useFakeTimers();
     mockResizeObserver();
     service = TestBed.inject(ResizeObserverService);
     fixture = TestBed.createComponent(TestHostComponent);
@@ -63,71 +58,63 @@ describe('ResizeObserverService', () => {
   afterEach(() => {
     subscription?.unsubscribe();
     restoreResizeObserver();
+    vi.useRealTimers();
   });
 
-  it('emits initial size event when asked', async () => {
+  it('emits initial size event when asked', () => {
     subscribe(true);
-    await timeout(10);
+    vi.advanceTimersByTime(10);
     expect(spy).toHaveBeenCalledWith(expect.objectContaining({ width: 100, height: 100 }));
   });
 
-  it('emits no initial size event when not asked', async () => {
+  it('emits no initial size event when not asked', () => {
     subscribe(false);
-    await timeout(10);
+    vi.advanceTimersByTime(10);
     expect(spy).not.toHaveBeenCalled();
   });
 
-  it('emits on width change', async () => {
+  it('emits on width change', () => {
     subscribe(false);
     detectSizeChange(200, 100);
 
-    // Skip test when browser is not focussed to prevent failures.
-    if (document.hasFocus()) {
-      // with throttling, this shouldn't fire just yet
-      await timeout(20);
-      expect(spy).not.toHaveBeenCalled();
+    // with throttling, this shouldn't fire just yet
+    vi.advanceTimersByTime(20);
+    expect(spy).not.toHaveBeenCalled();
 
-      await timeout(150);
-      expect(spy).toHaveBeenCalledWith(expect.objectContaining({ width: 200, height: 100 }));
-    }
+    vi.advanceTimersByTime(50);
+    expect(spy).toHaveBeenCalledWith(expect.objectContaining({ width: 200, height: 100 }));
   });
 
-  it('emits on height change', async () => {
+  it('emits on height change', () => {
     subscribe(false);
     detectSizeChange(100, 200);
 
-    // Skip test when browser is not focussed to prevent failures.
-    if (document.hasFocus()) {
-      // with throttling, this shouldn't fire just yet
-      await timeout(20);
-      expect(spy).not.toHaveBeenCalled();
+    // with throttling, this shouldn't fire just yet
+    vi.advanceTimersByTime(20);
+    expect(spy).not.toHaveBeenCalled();
 
-      await timeout(150);
-      expect(spy).toHaveBeenCalledWith(expect.objectContaining({ width: 100, height: 200 }));
-    }
+    vi.advanceTimersByTime(50);
+    expect(spy).toHaveBeenCalledWith(expect.objectContaining({ width: 100, height: 200 }));
   });
 
-  it('can handle multiple subscriptions on same element', async () => {
+  it('can handle multiple subscriptions on same element', () => {
     subscribe(true);
 
-    // Skip test when browser is not focussed to prevent failures.
-    if (document.hasFocus()) {
-      const spy2: Mock<(dim: ElementDimensions) => void> = vi.fn();
-      const subs2 = service
-        .observe(component.theDiv().nativeElement, 50, true)
-        .subscribe(dim => spy2(dim));
+    const spy2: Mock<(dim: ElementDimensions) => void> = vi.fn();
+    const subs2 = service
+      .observe(component.theDiv().nativeElement, 50, true)
+      .subscribe(dim => spy2(dim));
 
-      await timeout(20);
-      expect(spy).toHaveBeenCalledWith(expect.objectContaining({ width: 100, height: 100 }));
-      expect(spy2).toHaveBeenCalledWith(expect.objectContaining({ width: 100, height: 100 }));
+    vi.advanceTimersByTime(10);
+    expect(spy).toHaveBeenCalledWith(expect.objectContaining({ width: 100, height: 100 }));
+    expect(spy2).toHaveBeenCalledWith(expect.objectContaining({ width: 100, height: 100 }));
 
-      detectSizeChange(200, 100);
+    detectSizeChange(200, 100);
 
-      await timeout(150);
-      expect(spy).toHaveBeenCalledWith(expect.objectContaining({ width: 200, height: 100 }));
-      expect(spy2).toHaveBeenCalledWith(expect.objectContaining({ width: 200, height: 100 }));
+    vi.advanceTimersByTime(100);
+    expect(spy).toHaveBeenCalledWith(expect.objectContaining({ width: 200, height: 100 }));
+    expect(spy2).toHaveBeenCalledWith(expect.objectContaining({ width: 200, height: 100 }));
 
-      subs2.unsubscribe();
-    }
+    subs2.unsubscribe();
   });
 });
diff --git a/projects/element-ng/resize-observer/si-responsive-container.directive.spec.ts b/projects/element-ng/resize-observer/si-responsive-container.directive.spec.ts
index f65112539..f893a43c0 100644
--- a/projects/element-ng/resize-observer/si-responsive-container.directive.spec.ts
+++ b/projects/element-ng/resize-observer/si-responsive-container.directive.spec.ts
@@ -41,7 +41,10 @@ describe('SiResponsiveContainerDirective', () => {
     element = fixture.nativeElement;
   });
 
-  afterEach(() => restoreResizeObserver());
+  afterEach(() => {
+    restoreResizeObserver();
+    vi.useRealTimers();
+  });
 
   const testSize = async (size: number, clazz: string): Promise<void> => {
     vi.useFakeTimers();
diff --git a/projects/element-ng/search-bar/si-search-bar.component.spec.ts b/projects/element-ng/search-bar/si-search-bar.component.spec.ts
index 85b06da85..de6f5f41e 100644
--- a/projects/element-ng/search-bar/si-search-bar.component.spec.ts
+++ b/projects/element-ng/search-bar/si-search-bar.component.spec.ts
@@ -175,6 +175,10 @@ describe('SiSearchBarComponent', () => {
   });
 
   describe('debounceTime', () => {
+    afterEach(() => {
+      vi.useRealTimers();
+    });
+
     const fakeInput = (text: string, element: HTMLElement): void => {
       const input = getInput(element);
       input.value = text;
diff --git a/projects/element-ng/side-panel/si-side-panel.component.spec.ts b/projects/element-ng/side-panel/si-side-panel.component.spec.ts
index ccafb7fb7..8d83737f3 100644
--- a/projects/element-ng/side-panel/si-side-panel.component.spec.ts
+++ b/projects/element-ng/side-panel/si-side-panel.component.spec.ts
@@ -68,6 +68,10 @@ describe('SiSidePanelComponent', () => {
     service = TestBed.inject(SiSidePanelService);
   });
 
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   it('should create', () => {
     expect(component).toBeTruthy();
   });
diff --git a/projects/element-ng/split/si-split.component.spec.ts b/projects/element-ng/split/si-split.component.spec.ts
index 5dd872131..037be96f4 100644
--- a/projects/element-ng/split/si-split.component.spec.ts
+++ b/projects/element-ng/split/si-split.component.spec.ts
@@ -410,7 +410,8 @@ describe('SiSplitComponent', () => {
         });
 
         it('should save ui state ', async () => {
-          // cannot use jasmine.clock here
+          // Drain the async chain: asapScheduler -> parts.changes -> setTimeout(refreshAllPartSizes)
+          await new Promise(resolve => setTimeout(resolve));
           await new Promise(resolve => setTimeout(resolve));
           wrapperComponent.splitPart().toggleCollapse();
           const uiStateMock =
@@ -435,15 +436,17 @@ describe('SiSplitComponent', () => {
           fixture = TestBed.createComponent(WrapperComponent);
           wrapperComponent = fixture.componentInstance;
           wrapperComponent.sizes = [20, 60, 20];
-          // We need this here to run checks after async tasks completed.
-          fixture.autoDetectChanges(true);
           element = fixture.nativeElement;
         });
 
         it('should load and configure split parts', async () => {
-          // cannot use jasmine.clock here
+          fixture.detectChanges();
+          // Drain the async chain: asapScheduler -> parts.changes handler ->
+          // restoreFormUIState() -> uiStateService.load().then() -> setTimeout(refreshAllPartSizes)
+          // Multiple setTimeout rounds are needed to flush the nested async operations.
+          await new Promise(resolve => setTimeout(resolve));
           await new Promise(resolve => setTimeout(resolve));
-          await fixture.whenStable();
+          fixture.detectChanges();
           expect(wrapperComponent.measureSize1()).toBeCloseTo(200, 0);
           expect(wrapperComponent.measureSize2()).toBeCloseTo(200, 0);
           expect(wrapperComponent.measureSize3()).toBeCloseTo(100, 0);
@@ -510,6 +513,8 @@ describe('SiSplitComponent', () => {
         wrapperComponent.scale3 = 'none';
         await runOnPushChangeDetection(fixture);
         fixture.detectChanges();
+        // Drain the async chain: asapScheduler -> parts.changes -> setTimeout(refreshAllPartSizes)
+        await new Promise(resolve => setTimeout(resolve));
         await new Promise(resolve => setTimeout(resolve));
 
         expect(wrapperComponent.measureSize1()).toBeCloseTo(200, 0);
diff --git a/projects/element-ng/tabs-legacy/si-tabset/si-tabset-legacy.component.spec.ts b/projects/element-ng/tabs-legacy/si-tabset/si-tabset-legacy.component.spec.ts
index 5f3d8bb73..5a71ab128 100644
--- a/projects/element-ng/tabs-legacy/si-tabset/si-tabset-legacy.component.spec.ts
+++ b/projects/element-ng/tabs-legacy/si-tabset/si-tabset-legacy.component.spec.ts
@@ -199,9 +199,11 @@ describe('SiTabset', () => {
   it('should handle focus correctly', async () => {
     testComponent.tabs = ['1', '2', '3'];
     fixture.detectChanges();
+    vi.advanceTimersByTime(1000);
     await fixture.whenStable();
     if (document.hasFocus()) {
       getElement(0).focus();
+      vi.advanceTimersByTime(1000);
       await fixture.whenStable();
       expect(getElement(0).getAttribute('tabindex')).toEqual('-1');
       focusNext();
diff --git a/projects/element-ng/theme/si-theme.service.spec.ts b/projects/element-ng/theme/si-theme.service.spec.ts
index b127ab1a7..03159e851 100644
--- a/projects/element-ng/theme/si-theme.service.spec.ts
+++ b/projects/element-ng/theme/si-theme.service.spec.ts
@@ -30,7 +30,10 @@ describe('SiThemeService', () => {
   };
 
   beforeEach(() => (themeSwitchSpy = vi.fn()));
-  afterEach(() => localStorage.removeItem(SI_THEME_LOCAL_STORAGE_KEY));
+  afterEach(() => {
+    localStorage.removeItem(SI_THEME_LOCAL_STORAGE_KEY);
+    vi.restoreAllMocks();
+  });
 
   describe('with theme type auto', () => {
     it('should set theme to `light` if preferred', () => {
diff --git a/projects/element-ng/toast-notification/si-toast-notification.service.spec.ts b/projects/element-ng/toast-notification/si-toast-notification.service.spec.ts
index dcb01954a..10a3fd3fd 100644
--- a/projects/element-ng/toast-notification/si-toast-notification.service.spec.ts
+++ b/projects/element-ng/toast-notification/si-toast-notification.service.spec.ts
@@ -17,6 +17,10 @@ describe('SiToastNotificationService', () => {
 
   beforeEach(() => (service = TestBed.inject(SiToastNotificationService)));
 
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
   it('should be created', () => {
     expect(service).toBeTruthy();
   });
diff --git a/projects/element-ng/vitest-base.config.ts b/projects/element-ng/vitest-base.config.ts
index 88cceb104..efd1bf92b 100644
--- a/projects/element-ng/vitest-base.config.ts
+++ b/projects/element-ng/vitest-base.config.ts
@@ -13,8 +13,7 @@ export default defineConfig({
   test: {
     env: {
       TZ: 'UTC'
-    },
-    isolate: true
+    }
   },
   resolve: {
     dedupe: ['@angular/core', '@angular/common', '@angular/platform-browser']
diff --git a/projects/element-ng/wizard/si-wizard.component.spec.ts b/projects/element-ng/wizard/si-wizard.component.spec.ts
index 8cc1966db..2bb820b9b 100644
--- a/projects/element-ng/wizard/si-wizard.component.spec.ts
+++ b/projects/element-ng/wizard/si-wizard.component.spec.ts
@@ -364,6 +364,10 @@ describe('SiWizardComponent', () => {
   });
 
   describe('steps with lazy loading', () => {
+    afterEach(() => {
+      vi.useRealTimers();
+    });
+
     it('should render steps if they are loaded lazily', async () => {
       hostComponent.steps.set([]);
       fixture.changeDetectorRef.markForCheck();