Is there any logic or flow that would impact whether the respondent sees that question at all? EG: if the "required" question is Q8, but Q8 is only seen based on how Q7 is answered, OR Q8 is only seen as part of a block that not everyone is presented with, then the respondent would not be required to answer Q8 because they did not see it.

Also worth checking: was the "requirement" placed on the question after it was published? If the question was set to be required but the survey was not re-published with that setting, the Preview would appear correct but the live version of the survey would not reflect the change.

I’m having the same issue and have no errors in logic (using branches) and the requirement was not placed on the question afterwards. It seems like the initial question (which then branches) is not being recorded. Is this perhaps a bug?

Hi CarolK
Thank you for your response and no, there are no faults with the display logic as it is an independent question. There isn't a problem with the change not being published as I published it multiple times.
The question type is multiple choice and there are about 1000 dropdowns to choose from.
HilaryT I think you're right, it seems like a bug to me too.
Is there anyone from Qualtrics who can look into this?
Thanks!

You probably have to contact support to get assistance, if the issue is a bug. To help them troubleshoot (especially since you have so many variables to potentially check), I'd suggest you also download the results with Advanced settings, to flag questions that have been seen but not answered as -99. That way you can confirm absolutely that the question IS being seen AND not answered despite the setting being applied that should prevent respondents from moving on without answering.
Best of luck in getting resolution!