Report says "NA" for all user response but the user received a score?

I have a user that has completed several of my courses and the accompanied quizzes but when I ran the report to see what questions they got correct/incorrect, every response was listed as "NA" which I'm assuming means "Not Attempted". The issue I have with this is the user actually completed each course/quiz and received a score. I know that the course is set up correctly as this is the only user that I have seen this happen to out of the 15 or so other participants. There are a few other users that I see an NA response for but they also scored a 0 on the course as they did not complete it so I have no issue with that. Any idea as to what could be wrong? Thanks!