About one in every four times I play bb_carnage, somewhere in the area just in front of the large door that opens after the first two minutes, I am firing merrily away at zombies, and, finding that no more are around, I proceed towards the door. All of a sudden, I stop for no reason, hear the zombie attack noise, and I start turning into a zombie. The nearest zombie is about 10 yards away, and is just getting up off the ground. I continue to get knocked around. I look and fire blindly around and hit nothing. There are no player zombies either. Anyone else notice this problem?

I believe it may be similar to the invisibility bug on TS that occurs sometimes, where the player model, for whatever reason, has not loaded.

I have only encountered this problem on that certain spot on bb_carnage. Has anyone else?

I have, also on bb_carnage, though in the spawn area. I know it was a zombie because I saw it vanish and was able to kill it after confirming its location...