When you get OOS you get multiple losses, i.e. OOS in 3v3 gives you 3 losses. If you look through anyone's profile you'll see bunches of these.
no that cant be all of it - i have only had 2 OOS in last month but i have 60+ of these losses. I just got 4 more losses for watching 2 of my clanmates play a 1v1.
I think I also remember seeing it happen sometimes when one player drops out of the game. I.E. if you were watching someone and another player who was watching drops...you get a loss even though the game continues.