Another glitch?

[Corpfox]

I got invited to join a L4D game but there was only 3 out of 8.

I waited for 30 mins then I left.

All the sudden, my LAMB 2 SLAUGHTER, has been unlocked and oddly, OUTBREAK, is locked.

http://steamcommunity.com/profiles/76561197960914651/stats/L4D

Anyone else got something like that?

 

[Tek7]

All the sudden, my LAMB 2 SLAUGHTER, has been unlocked

I had the same thing happen to me last night. I loaded up single player mode to test the video card on my new notebook and when I exited the game, I was awarded LAMB 2 SLAUGHTER. Weirdness.

 

[Sacrifice]

The same thing happened to me. I was going to play a game with some people, but the game filled up before I got there. I exited the game and also got the "Outbreak" achievement. Odd!