I suspect I know the answer to this, but I thought I would ask anyway.  We have a choice poll that was created and 2 of our students are not showing up under unanswered (we have that option setup).  One of those students indicates she did make a choice, which is also not showing up.

The only outstanding item I can find is that the instructor confirmed that she took an older poll of the site and just changed the times and offering.   She then reopened it and is now having the above challenge.  I recreated the same poll, fresh and everyone is showing up.  My current recommendation is for her to use the new refreshed version.  But, we would still love to figure out what is up with the choice poll and whether an older choice poll can be used, and edited.