Changing default auto-populating text for failurebox on software sim clickboxes.

This is a weird problem, I never have experienced that the Failure caption embeds the correct answer. Have a look at this assessment example which I posted in the eLearning community recently:

Simulation assessment to test Captivate skills - eLearning (adobe.com)

I always change to 'shape' instead of 'caption', and later on decided to take the Failure messages out completely but I don't remember ever having seen the AutoFill leading to embedded hints in the messages at all. Click boxes nor Text Entry Boxes have a default label in simulations and you are correct, the messages in Quiz Preferences are not at all used in simulations. Did you use the Assessment or the Training mode? I may try to double-check your problem, but you need to turn off Autofill in the application you are capturing (not for the Failure message however, it is always a recommendation).

Can you tell the exact version of Captivate you are using please? You find the full version number under Help, About Captivate. I am stil on 11.5.5.553 because the recent version 11.8 has too many bugs from what I read in this forum.