Well I thought the lastest build fixed it but I think I have determined the real culprit. Today it seemed to happen again during a test and looking at it closely and more students seem to ask about it. I discovered it had to do with the marks the student was being shown differing from the marks I was seeing on the results screen.
I posted a follow up here http://moodle.org/mod/forum/discuss.php?d=65166#p648128 in a different topic that more relates to what I am seeing.