I had a problem with the Q&A plugin in that the pages that should display a full list of questions and unanswered questions actually displayed posts from my blog.
After much searching, changing themes, disabling plugins, etc. I found the problem:
When I disabled CustomPress the Q&A pages displayed correctly. Of course I couldn't just delete CustomPress as the site I was building had very specific custom posts that were an integral part of the site.
I played around with the settings in CustomPress and found the answer!
The "On Archive pages, display these post types" setting should be set to default.
I had unchecked default so that only certain post types would display on archive pages. Now I have to live with unwanted post types on my archive pages but I prefer that to not having Q&A working.
Perhaps in the next versions of Q&A and CustomPress they can be made to play nicely together so that I can have archive pages the way I want and still see questions?
I hope this helps someone; I saw there were a few similar threads from a few years ago but no real resolution to the problem.