I once had a 30 questions aircraft type conversion exam, where 10 of the 30 questions had nothing whatever to do with the type (so I had not reviewed those aspects at all). One question (which I got wrong) had as the "correct" answer, a violation of an air regulation (which is exactly why I did not choose it). I failed the exam by one question.
I complained, and it was agreed I should have passed, and I was sent a letter saying I had. I'm told the exam was changed.