Sonos & Harmony Volume Issues - Please help!

I have a Sonos Playbar and a Harmony Elite Remote (with Hub). For the first few months, I had them set up normal with the Harmony Hub controlling the Playbar volume (via wifi). It worked okay, but my Harmony Hub frequently disconnects due to its own issues with Mesh Wifi networks. Obviously, if I tried to adjust the volume during a time when the hub is disconnected, it doesn't work or the volume would spike and then I wouldn't be able to turn it down without using the Sonos App. Due to this, I decided to change the Harmony settings and use "Remote Only" to control the Playbar Volume (via IR).

After changing to Remote Only and updating the remote, it seemed to work great for a couple hours (without even updating Sonos remote settings in the Sonos app), but then late last night, it stopped working and kept doing the volume spike referenced above (i'd hit volume down and it would get real loud and then could only be fixed by Sonos app). Of course, this did not make my wife happy as our two young children were asleep. At that point, I tried to reprogram the Sonos remote within the Sonos app, but the Playbar did not seem to recognize the Harmony button presses, so I was unable to complete the setup.

Please help!