Thanks for the suggestion, but alas, it didn’t work.ย The results were the same.
I also tried removing everything else out of the network – just the BV7 and the BC8500 connected together (via the 1611), and found something unexpected – if I select a source on the BC8500 panel, the speakers don’t power on.ย They’ll only power on if I select a source on the remote.
I assume this is a limitation of the 1611, and that won’t work for me, so I’ll go back to using the BS4 in that room, I think.