Coding assessment was a simple program to parse and do some processing a file/data set. I tried not to spend too much time on it (about a day) but I separated the different stages of the processing "pipeline" into their own modules with interfaces between them, unit and integration testing, no dependencies.
Initially they liked my solution and moved me forward to the behavioral interview which was 2 engineering managers drilling me with "tell me a time you..." with follow ups ("what did you learn from that", "describe X tech you used").
I'm not sure why, but from the get-go the two managers definitely didn't want me to be there. Felt like a bad date.
It ended and I got rejected with a "actually your coding assessment solution was bad" email.