This didn't happen for methods, but it did happen for another subject, which I won't name here. Our first sac was ripped straight from VCAA exams from the previous two years (I'd actually gone over them the night before, so was fairly surprised when it came up). Then when we got the sacs back, a few of us had the same question wrong, so we went to the examiners report to check out why, turns out we were right and had the same working and result as the report. We went and showed the teacher, and even showed them the examiner's report, they stood to their (incorrect) working and we didn't get any marks for that question, even though we had exactly what VCAA would have wanted if it were an exam....
Tbh, if I were in the same situation you were in then it'd be slightly annoying. It would probably help if you can expose yourself to more sac-type questions outside of class, to help prepare for exams rather than knowing the questions on the sacs beforehand.