Process took ~3 months for four interviews or so, waiting multiple weeks between steps. I was given an offer at the end, but after accepting it they took back the offer citing internal restructuring. Incredibly unprofessional.

Interviewer was late and rescheduled 2 hours later. 2 hours later she was still late by about 15 minutes and appeared right before I was about to close the call. The interview itself did not have a lot of clarity. One thing I was dreading that there would be 6 stages of interviews, which is absolutely excessive. Later I got an automated rejection without any explanation, even thought the interviewer mentioned "strange that we never contacted you with such a strong profile". I must say the whole thing left a sour taste in my mouth, because I feel I was not respected as candidate nor as a person. Especially because interviewer's excuse was an issue with scheduling software, which felt like a nonsensical lie (like, can't you see the calendar?)