I have multiple players in my network (all 2.692) and usually control them via the web interface of my primary player.
This player has None selected for volume control.
When I change the active player via the Playback page, the volume dial stays disabled, even though this player has Hardware selected for volume control.
As a check, I also tried it the other way around (access the secondary player’s webinterface and switch to the primary player) and then it stays disabled.