The worst experience I've had with a take home problem was when the interviewer did not even run the program I submitted. As I explained the solution it became clear that the interviewer had not even looked at or run the program. It would have been easy, it was in Python.

To top it off the interviewer then sprung a surprise leetcode problem on me that had to work and was required to be written in a language ill-suited to the task. I bombed it and the interview ended. No one ever even ran my submitted program.