I have a Deco setup with 4 deco units. The main unit is an XE75 Pro connected configured in AP mode. It is connected to the main router via a TPLink 2.5Gbps Ethernet switch. Once every day the Ethernet connection between the main deco and the switch drops to 100Mbps. I can see that both from the network speed as well as the link speed LED on the switch. I have replaced all ethernet cables with new ones and the problem remains.

The problem goes away if I unplug and replug the ethernet cable connecting the main deco to the 2.5 switch. Which I guess forces the link to renegotiate speed and go back to 2.5Gbps. Also, I tried using one of the 1Gbps ethernet ports on the main deco, but the issue remains. Also, I connected the ethernet cable from the main deco directly to the router (bypassing the 2.5Gbps switch). Same issue. All this leads me to believe that the main deco is the one downgrading the ethernet speed to 100Mbps.

Any ideas/solutions?

See photo for details of my setup.