Similar experience to others here - they advertised for one position and then interviewed me for another (more like Head of Data Analytics). After 7 rounds of superficial 30 minute interviews, involving a total of 8 people and taking 6 weeks, I guess they realized that and rejected me.
Interviews were quite easy, because no-one seemed to be really that interested, or had enough time, to drill down into actual knowledge and experience, ultimately leaving you with the impression that this was part sales pitch and part high school popularity competition (quite common for startups, unfortunately). Again, like others here, this constantly left you in a state, post-latest interview, of whether you had answered the one 'gotcha' question correct or not that would allow you to proceed. I was half expecting a question about European vs. African swallows by the end.
Was rejected with a seemingly less than accurate 'we went with someone else', as the position remains open on both LinkedIn and their careers page. Ultimately, a disorganized mess of an interview process. Thumbs up to the recruiter though, who tried her best to navigate me through all of this - I don't think it was her first time doing that.