They were used for interviews for maths and CS, so I think it’s quite likely the candidates would have seen similar puzzles before, but I think that misses the point. This sort of puzzle is there so that the students can either present and an answer and the interviewer can start to dig into it with more questions, or so that the candidate doesn’t come up with an answer immediately and the interviewer can ask other questions that will help them reason things out.

The object is generally to explore how a candidate thinks. If it turns out they memorised logic puzzles and can’t explain them then they will not get through the interview.