Winning by forfeit doesn't coun ...

I don't know if this is a bug, but when I win a game because my opponent decided not to play for a week, it doesn't increment win counters. For example, I have won three shaolin games this way, via forfeit, and I still don't have the 'We Are One' achievement, and 'So Many Victories' hasn't incremented at all.
If this isn't a bug, but is supposed to be how it works, that's fine, but I'd like to know so I can start resigning games. My games list is usually full enough that I don't want to leave unplayed games in there for a full week if there's no difference to me between a forfeit win and my own resignation. (I don't care about the taunts, so stats are the only reason I care)