OK, from my four exams (Air Law, Met, Human Factors, Flight Performance & Planning) I only remember one question that really got me confused - FPP Q14 (Why is full flap selected during the approach and landing phase of a flight). The answer given is sufficiently ambiguous to have confused me in the exam (although I knew better, I chickened out and picked the Confuser answer - which was wrong in the context of the exam). I cant remember finding wrong answers in the other three, although Air Law was a long time ago now. The Met exam was very different to the Confuser, so that doesn't really count.
If there are wrong answers in Nav and Aircraft General then I'd like to know too