Hi Kevin

If you add a question to an existing feedback that has been responded to then users who have already responded won't be able to answer the new questions as they won't have any more attempts left.  In most cases you would only allow one attempt .

If you want users who have previously completed the Feedback and used all their attempts to complete the new question then you could create a new feedback so they would need to complete this again. This would mean all the answers are in one activity for new and old users.

It might be possible to input previous feedback replies but not if anonymous feedback option is selected.

Regards