FWIW, I have conducted a lot of interviews (for both DS and SWE) at multiple companies, and at none of them has it been remotely the case that "having any bugs in the whiteboard code is a fail".https://twitter.com/minimaxir/status/951117791624445954 …
I always asked for feedback/reasons when I failed an interview. Only got any feedback at all about 1/3rd of the time, and what feedback I was given was only 50% honest/useful. Mostly CYA legal liability issues dominate and nobody tells you shit.