@yves_b Ah! That clears things up. I wasn't sure why there were 4 interfaces in these two bridges, considering the X55 only has 3 ports. This makes so much more sense now. If the naming assignment is...

I did some more testing since posting this, including a factory reset. After the factory reset, it was Port 3 that was not connecting instead of Port 2. This showed me that the issue is likely caused...

I have an X55 as my main unit, with an X50 connected over Ethernet as a secondary unit. This set up was working fine up until a few days ago when I would wake up in the morning to find the X50...