When I'm using the web player to play music it doesn't show what I'm listening to when I'm browsing other albums, except for a few rare cases. Also, my girlfriend is listening as well to the web player and only once have I seen what she's listening to, even though she listens all day every day.
The log reports what music is playing without a problem, so I'm not sure what the cause of this could be. It shouldn't be the web player's fault because Subsonic knows what music is being requested as the web player requests it.