Thor::Shell::Basic.new.ask outputs duplicated lines

[daddygongon]

The following code

question = "Q#{idx+1}: '#{ew[0]}' ? -> "
input = Thor::Shell::Basic.new.ask question

outputs duplicated lines with a long string:
Q1: '内省する/However, not all learners are equally able to --- and to report their t
Q1: '内省する/However, not all learners are equally able to --- and to report their t
houghts.' ? ->

How can I avoid it?