Anyone else have this? Every couple of says I'll see a notification that I've unlocked some achievement in a game, which is fine but it's generally a game that I'm not playing. Also, it's usually some really advanced or rare achievement that a very low percentage of people have. Most of them are things like here's one for completing the game, which I have somehow managed to get without even finishing the first level. It seems to be happening to me a lot, like once a day at least.

Only thing I've ever seen like it would be with Arkham City. I played all the way through and then one day, long after I had stopped playing, every achievement in the game triggered all at once.