I would say most of them are deliberate, not even sure I should count any as a mistake. Think about it, why is the money always less? Why didn’t they just send above the required amount? I would even take that particular one as deliberate because some people might not check the full details, but once they see almost a three or four digit amount from the notification they will assume it’s correct. The plan is to make the seller release coins, and that way they win. So next time OP should always report such attempts imo.