I was approached by their recruiter and had a few pleasant phone calls with her, followed by a 30 min call with the person I would be reporting to. They sent me a coding challenge which I completed and submitted, then went through a 4-hour onsite interview with various stakeholders. It seemed to go well and I felt pretty good about it. I was told that there was one other candidate they were interviewing and that I would hear something soon. I then got a generic rejection email from the hiring manager. All that is fine, but then I see the same opening posted online, which makes me wonder what is going on? I felt a bit used or something.