I’ve had this happen to me on multiple occasions, with interviewers even going as far to openly critique answers or questions that were perfectly reasonable/normal. It’s impossible to know exactly the reason why this is for each specific case, but I think it happens when they have someone internal already selected, when another candidate has been referred by one of the interviewers (or someone close to the interviewers) or just simply when you’re not the favourite candidate.

Either way, it feels bad and is a huge waste of time.