Not really crazy but last year I had a German speaking paper go up by 5 UMS pushing my overall grade up to an A, and a C3 paper go down by 4 UMS. This year my class are having a bulk remark of Physics unit 4 because most of us got U grades on it. In my case the anomaly brought my overall grade down to a C and now I've lost my firm and insurance, and I've had to change course because even in clearing no uni would let me study physics with a C at A level