Most rounds were reasonable, except for one coding round. The interviewer changed his mind on the interview question within the first five minutes, deciding not to ask the prepared question and instead asking for something else without a finalized problem framing. It took us twenty minutes to frame the problem, and even after I received his approval on the problem setting and finished the implementation, the feedback I got afterwards was that it wasn't what he was asking for.

Firstly, it was a coding round, not a design round. Secondly, the whole interview was one hour, and if you can't frame a problem within twenty minutes, what's the point of changing the question?

As a candidate, my expectation was a coding round (that's what was on the agenda), so I tried to get the coding done on time. Apparently, I think the interviewer arbitrarily changed his mind and made it a design round without asking.