Four rounds of interviews with the team, each round touched on different skills that you could provide for the team, each member was super transparent and the interview process lasted ~3 weeks

Had three interviews, all were pleasant and positive. On the third interview I was surprised to learn that it was the last step, and was asked if I wanted the job, or even another similar position that we briefly discussed. I mentioned some hesitations given that they had reached out to me just as I was accepting a promotion at my current company. Interviewer said they completely understood, but asked me to take a week to think it over and get back to them since this was the last interview in the process. Even gave me their direct contact info so I could follow up if I had more questions, and directed me to their recruiter for clarifications on some of the benefits. Immediately follow up with the recruiter, met with silence for a few business days, and then a confusing email that there is actually more interviews in the process 'should they choose to move ahead with my application', and could not clarify benefits at this time. Next day I received a rejection email. Beyond frustrating.