@ImtiazAli thanks for the link. I did go thru that previous to posting, and all signs point to this particular unit having faulty ports. My current set up works in every way except this problem unit...

I also connected the problem unit directly to the main unit. Still shows Wi-Fi connection, no Ethernet connection. I then connected the problem unit to the modem and got a solid red light.

I just set up a Deco X60 mesh network with 3 units. In Wi-Fi they all work fine. I did an Ethernet backhaul and one of the satellite units will connect to the Ethernet via a switch, the other unit...