Some friend of mine was interviewing for a junior position at some startup in London and he noticed one of the interviewers secretly recording him while asking a strange whiteboard question all from memory which they don't use in production at all. The interviewers ridiculed and belittled him straight through the interview with the recording and he told me he found the place very unwelcoming.
The thing is, it is usually the self proclaimed 'senior engineers' who have less than 4 years of experience at a single company who have also been bullied that are most likely to be this arrogant and cannot ask the right questions, thus cannot interview juniors properly; only to feel better about themselves afterwards.
After this he told me that the company in question raised two series rounds in less than 5 months; a statment that they're haemoraging cash. I'd say he dodged an unprofitable bad egg anyway.