Just to make sure this thread is alive and Apple realizes that latest AE is faulty... here another one with the same issue. Returned the first one after 9 months and got a new one, doing same stuff.
I'll describe my power configuration as a reference:
My AE is plugged to a power strip together with a lot of other gadgets (router, NAS, fiber ONT, TV, tivo...) and that strip is plugged into the filtered socket of a PLC, that is plugged to the wall socket. I have a twin wall socket, unused as recommended by PLC vendor, to make sure all noise get filtered by the PLC so the bandwidth obtained is optimal ...
Reading this thread, maybe a super sensitive power supply is the origin of this crappy AE.
i'll try moving the AE plug to the second wall socket and see if that makes a difference...
I'll come back and update
C'mon Apple, do something!!