[Levansic]

CAN cables don't care which port they connect to, as long as the chain is terminated. The CAN bus is a party line, where all modules are listening at all times.

There is no directionality to the bus.

If a cable and port appear problematic, then you should treat that connection as suspect. Check the cables and ports thoroughly, as something is wrong in that link. If you move the cables to other ports, and the problem goes away, you may have just delayed the problem, and hid it somewhere else.