Genie has ALWAYS had network issues (going back to the HR34, which didn't even have WiFi built-in). They are not going to fix anything (especially not AT&T), it is working as intended for them.

By the way, HR44/54 Genie (and probably the new HS17 as well) have 4 MAC addresses. There is the WiFi MAC, Ethernet MAC, MoCA MAC, and a server MAC (not sure what hardware in the Genie that last one generates from).
And has been noted on these & other forums, those MAC addresses don't always follow their physical connection. Somehow the receiver will switch to one of those MAC addresses for no reason, even if that physical layer is not technically being used. It is some wonky crap!