Feedback master query

I've just had to delete my customised feedback retry master and manually put the response in for each quiz slides layer because I have a mix of multiple questions / true/false /  multiple responses. 

In answering a multiple response incorrectly I found that it showed the background image but not the response.  I also tried manually adding the response to this particular layer but I got the same error with just the background and no response.

I've also been advised that if you don't put your customised feedback responses into the masters first then these sort of issues can happen.

Any clues why this happens or how you could fix it without having to manually fix it?  My project now works but I'm just curious.