Ref T11809. We show a red dot next to a username to indicate that the user is away (on vacation, in a meeting, etc).
It's not very obvious what this means unless you know that's what it is: when you click the username or view a hovercard, there's no visual hint about what the red dot means. It does say "Away", but there is a lot of information and it doesn't visually connect the two.
Connect the two visually by putting a red dot next to the "Away" bit, too.