I understand the desire to cut other potential variables, but what I'm experiencing doesn't jive with that assessment, so I don't see the need to do that. It is 100% repeatable, and the testing I've done is not strictly over WiFi - even a hardwired device to the AP exhibits the same repeatable...
I have an access point connected via goCoax MA2500D on ATT Fiber (2.5 Gbps into the home). It is a direct coax connection between adapters, and the rest of the coax in the home isn't used/connected to anything. The issue I just stumbled across is my adapter seems to be slowing downloads from...