Right Surround Play:1 not working

I've had a BAR, SUB and 2 play:1s in surround set up for a while, and have recently had in issue where the right surround speaker won't make any noise, though it's added and I can see it the list of my devices in the "About my Sonos" part of the settings menu. I submitted a diagnostic, and that number is 8022640.

I recently got a BOOST, and just set that up by turning off the wifi in the house, connecting the the BOOST and getting all the speakers re-added, so it looks like everything is appropriately on the BOOST network. I even tried swapping out that right surround Play:1 with a different one thinking it might be the individual speaker. The result was the same - no sound out of it. The Left Surround speaker works fine! Weird, right? All the other speakers around the house are working fine, those consist of a few more play:1s and a CONNECT. I tried running Trueplay, and it gave the me the error that it couldn't hear the speaker. I've power cycled all the components, removed and re-added, all to the same effect. I did have a
similar problem with the SUB at times, but that's currently working. The problem occurs both with music and with TV feeding the speakers.

I did also recently link up my Sonos system to Amazon Alexa, which seems to be working fine, other than right surround in the livingroom.

Anybody have any ideas?