I think there might be a bug in the code that handles the volume from an endpoint. I am running RopieeXL (6/13/2020 build). I am running the Roon remote (latest version) on an iMac and controlling a DAC across the room.
The touch screen behaves like you’d expect with play pause, ff and rewind. The state of playback on this endpoint is shown in the remote app nicely. And it is bidirectional, in that the play/pause state is shown in sync in the remote and on the touch screen if I hit play pause on either device. The time is synced and correct in both places as well.
However volume control is not synced. If I change the DAC hardware volume in the roon remote, the volume level is properly reported on the touchscreen. But if I change the volume on the touschscreen, it is NOT being reported back and the volume in the remote app doesn’t reflect what happened on the touch screen. This means that if I turn the volume down on the screen, and I try to turn the volume up or down in the remote app, it jumps to where the remote app thinks the volume was, which can be very different than what the real volume was via the touch screen.