It's hard to explain in detail, but in essence, during the final round, I was asked to make a judgement call about the major cause of a problem. The interviewer asked me twice if I would like to change my mind and pick the other option. I didn't budge from my decision, and it turned out that in the actual case the reason I picked turned out to be the underlying cause of the profitability problem. The key takeaway is that you should seriously consider the merits of the alternatives a case interviewer suggests to you, but never change your answer simply because you get the impression that the interviewer wants you to.