I found a problematic first answer while reviewing, and went to edit it to clean up the terrible grammar (this helps me to think through questions). Instead of letting me edit, it said, "This post has been deleted." After navigating back to the review, I clicked "I'm done," thinking, "Oh, I guess this one's just been taken care of."
At this point, it informed me that I'd failed an audit. Okay, no problem, that happens occasionally. So I tried to go to the next question, which generated an error message -- probably related to the deleted answer I tried to edit -- at which point I hit back again. And that's when it told me I'd failed too many audits and couldn't review anymore.
I'm not sure why it didn't trigger as me passing the audit when I clicked edit, but there should be some kind of protective mechanism for visiting an audit fail message page a second time.
I hope this makes sense. It's obviously not easily reproducible, unfortunately, or I'd try to go back and be clearer.
It also seems like I may have hit a perfect storm of bugs that mostly don't arise in the wild very often.