This is most unorganised interview process I've ever experienced in my life. They schedule interviews at random days and random time, without even confirming availability.
They don't provide any feedback. After 4 rounds of interview they've sent generic rejection email, like nothing had happened. I'd understand if it was just automated response after initial CV screening, but i can't believe that after investing my time in those chaotic interview rounds I haven't deserved a single piece of feedback? Head of HR was failing to provide any feedback either, hiring manager didn't say a word as well.
I can imagine that their culture is to keep things hush hush and glad I didn't proceed with them.