Comment by amluto

Answering my own question: CEC is electrically unrelated to DDC/EDID. The EDID data tells each source its physical address, and then the devices negotiate over CEC to choose logical addresses and announce their physical addresses. This is one way to design a network, but it’s not what I would have done.

I wonder if a malfunction in this process is responsible for my AVR sometimes auto-switching to the wrong source.