Inaccurate representation of friend status

A friend of mine shows to be online but away, however, when i send him a game invitation, i'm told he's already in a game. Which is the actual truth.

Also at times my friend list shows my friends to have been "In a game" for well over an hour when they've only been in a game for a few minutes or even 20-30 minutes, but never the length of time displayed.