Network card in a server stops receiving messages once the card is moved into another slot

[Fingercomp]

Steps to repro:

1. Set up a server rack with two servers:

   

2. Connect the network cards to the same side:

   

3. At this point the network cards can exchange messages with each other, as expected.

4. Now open one of the servers' GUI (by clicking at where it's rendered in the rack model) and move the network card to another slot.

5. Observe that the server rack seemingly retains the network card's connection. However, it's not actually connected to that side, and the network card is not reachable over network from the other server.

Here's a video that demostrates the bug:

out.mp4

The video also shows a workaround: reconnect the network card manually (i.e., disconnect it and connect again).