Garbled Quiz

Hello... we sometimes encounter a problem whereby quiz questions become garbled.  Text will cover other text and answer boxes/buttons will disappear or appear in the wrong place on the screen (see attached).  Republishing to our LMS sometimes clears the problem, but other times we have found it expedient to just place the course in a whole new 'bucket'.  Most times, we cannot replicate the problem in-house during testing or when informed of the problem by our users.  Has anyone else had this problem and if so, do you know how to fix it?  

We are using Storyline 2.