LTM networking issue:

That is correct, but it also depends on whether we have an active listener for that conversation. If you have a conversation that goes back by a different route, we may well use that instead. Bridged networks are notoriously difficult to troubleshoot, and your best bet may be to open a case with Support and have them walk through a packet capture of the problem.

If you're comfortable with packet capture analysis, that may be your best bet moving forward, as well. Remember that you will have to track MAC addresses as well as IP addresses since the IP address will not change across the network.

I would suggest a packet capture on the BigIP on 0.0 to see what the BigIP sees, and another capture on both of the endpoint servers. This will allow you to quickly identify what is happening. If you use 0.0:nnn we will embed the Virtual Server in the packet, as well.