Ramp interview questions

First step was an initial screen with a Ramp recruiter Then there was an initial coding screen Then a hiring manager call Then a virtual onsite consisting of two coding questions and one systems design question and one hiring manager interview that was behavioral in nature

I got scheduled for a technical phone screen. I had prepared by going through Glassdoor, and got one of the questions that is repeated in the posts here. I had recently done another interview in which they asked something fairly similar, so I finished the problem in 20mins. The interviewer then gave me a "bonus" problem which was basically doing more HTTP calls with different edge cases. After making some progress, I ran out of time while handling another one of the bonus problem's edge cases. The next day I received a rejection with no explanation. It's weird to me that someone does pretty well because they were well-prepared, is given something called a "bonus", and then is rejected for no reason. I wouldn't have minded a rejection if I had done poorly, but the way it happened it seems the interviewer was accusing me of cheating, which is maybe a reflection on the company but more so on the interviewer himself.