Already fixed, new release this weekend with this fix included
I have updated to 2.787, and after a few hours, the devices don’t see eachother anymore (zone selection icon disabled).
With 2.789 the same experience. Zones lost after some time (I think hours.)
When I reboot a single device, the zones are visible on that device.
Switching to another device then disable the zone icon.
Same problem here.
Same network, unique name, no wireless repeater, same version of Volumio on every device, latest version 2.806.
For those looking now, I used to have this issue and it was because of a bug in my router firmware. I use OpenWRT and the 19.0.x releases had an Ethernet dropout bug until 19.0.5. When the network glitched it lost visibility of the Volumio devices.