Bad or missing endorsement? They must credit your account. Don't accept another answer.
Sometimes my bank on lesser checks they will just stamp on back "deposit only" In our area for many years now, the banks tend to never release funds from a check to the person instantly. That is why I was thinking that there could be a time factor if the discrepancy was spotted online quick enough.
I have been involved in some really heavy transactions where a lawyer was involved & the other party insisted on a "cashiers check" that supposedly was the same as cash --- supposedly less safeguards than a check or
credit card. Anybody who has had fun with
credit card disputes might give us a clue that is not all blue sky either.
MJ