Seems parent question still have other == 'Y'
https://github.com/LimeSurvey/LimeSurvey/blob/a529a3d1a2c553cbd2494b2ea6d801ca87478c4f/application/models/Question.php#L171

You can try to save as array before try again ?

Hmm, we have switched this question from a single choice question into an array questions. Could this be some kind of left-over?

Surely a single choice with other …

But : i think other='N' must be resetted when you save
Else : we have this error in 3.X

Maybe you can check with 3.X

1. Create a single choice Other == 'Y'
2. Save it
3. Update to array
4. Add other for subquestions

Then : dev can check how it's done in 3.X

At LS3 the error does NOT show up. I did the steps you described and could use "other" there.

image-2.png (11,518 bytes)   

image-2.png (11,518 bytes)   

Thank you !

Pull request : https://github.com/LimeSurvey/LimeSurvey/pull/2443

Improved pull request : https://github.com/LimeSurvey/LimeSurvey/pull/2443

Strange. I wasn't able to reproduce the issue on latest master (no patch applied).
@DenisChenu @Mazi Am I missing something?

image-3.png (37,694 bytes)   

image-3.png (37,694 bytes)   

You must

Create a single choice Other == 'Y'
Save and close it
Update to array
Save and close it
Add other for subquestions
Save and close it

Other are not resetted if question type didn't allow other

Capture d’écran du 2022-06-10 08-20-58.png (32,858 bytes)   

Capture d’écran du 2022-06-10 08-20-58.png (32,858 bytes)