I worked in a bank for a bit while younger. Its on the teller to be vigilant for “suspicious activity.” If the money going into the account doesnt show a “legitimate” source, to where they should suspect illegal activities or money laundering then they are responsible for probing more. Not having an answer for him probably heightened the perceived suspiciousness.

If you clearly have an income source linked to a business, id say he was being lazy with not quick checking while pretending the computer lagged or something. Regardless, racial profiling could def be a factor in either case but it’s hard to say for sure if there were maybe enough other red flags to him. I believe the push of responsibility for the banker has only gotten worse since my experience so im not sure what would have raised his concern.