I had five different calls and it took almost a month. Even had a test task. They also promised a reference check. I don't know why would you need so many calls to hire someone. Got a usual rejection letter, without any hope for feedback.
In short, I felt like a human on the first two calls, but then it started feeling a bit too much pressure and disconnected from people. So I would say, first two interviews being nice is an achievement of the interviewers and my luck, not the company wide thing. Which is proven by others here saying "interviews are probably biased". Pretty sure they are.
Anyway, here is the detailed experience.
First - HR call. Nothing new there, standard questions, standard experience. Was pretty open and fun.
Second - First call with a manager. This was a very good and friendly call, which made me believe that its going to be a good experience. The questions were not standard and the interviewer felt like they wanted to know me and not just put checkmarks.
Then I had to do a task and prepare for 2.5 hour call consisting of 2.5 interviews. Which is quite exhausting, I don't know why they do it that way, even Microsoft at least gives 15min breaks between interviews. I had none.
Third - Yet another manager call, which was very similar to the second one (just with a higher degree manager, not the CTO, someone in between, how many management levels there really should be?). It felt a bit more formal then the first one, but still ok. Usual questions about my experience and how I work with people.
Fourth - Test task discussion. Now this, this is always strange. You know how companies write "optional" points in the task, you never do them, and they scold you for that? Yeap. That happened again. So yeah, they tell you "just solve the problem in a few hours" -- its a lie. Spend a week on it, just so it looks and works good, has all the tests, all that stuff. Oh, and don't use advanced technologies, like DI, they don't know what that is. I had to explain to the interviewer who said "its first time I see that". There were a few issues here and there, nothing ever is perfect, and I figured them out quickly every time.
Fourth and a half - systems design. A usual systems design thing with a usual "ask questions and figure something out" step. Felt a bit disconnected from the team on that stage already. You know, like you say something and want to hear a reaction but get an empty stare? Or when you get interrupted several times because the interviewer doesn't want to hear you at all? Got both. Several of my questions about the task, I just got interrupted, with an annoyed voice, which is a very bad sign. Like, you SHOULD be able to ask questions, even if interviewer thinks they are stupid. Because that's the thing in real life, the most stupid questions about the product - turn out to be the most important ones. Regarding the architecture though, since I worked for a lot of small companies, and the architecture was simple usually. They wanted a big scalable thing, so I said "DB cluster probably should be enough, I never worked with them, but I think they work like that internally so it should solve the availability point". And got a blank quiet room. You don't feel good at that point, nobody says "ok" or "no" and you don't know how to proceed so I just get nervous and keep talking the same thing again and again. IDK, maybe I have to say "it will solve everything, its magic of technology" like people say when I interview them, maybe that's what works in so called real companies.
Fifth stage - I don't even know why it was there. A ten minute call with a recruiter afterwards, which was basically "we send you an email tomorrow, byeeee" type of call. Something noticeably wrong with the communication culture here, since its a "meeting that should've been an email"
Also, a funny thing to note, is that they said that I am going to interview with one person, but then another one came, this was happening on the third stage. Recruiters also juggled around, I think I had emails from 3 different ones. Maybe that already showed, that they didn't care much about my application at this point.