A sync problem

I think it's a know issue. I think it's a one of the games that you can't see in the your own game library.

Steam doesn't show it in libraries unless you put some playtime in it. Once you do, sync can detect it.

Its because it is DLC for the freely playable multiplayer only demo, so it causes some problems. If I remember correctly, it ends up detected once you have spent a decent bit of time playing it.

Its also a game that cracked online steam games use to hide that they are launching a cracked online version of a game.