I play BO2 on my PS3, and there's a weird thing going on with the camera ONLY IN ZOMBIES MODE (so in multiplayer I never run into this problem):

Sometimes, when I want to turn my view to left or right (to look left or right), the movement of the camera isn't smooth and continuous as it's in the multiplayer mode, it does something weird. It's like it starts normal, then does like a "pause" (almost stopping) and then continues normal. This is while holding the right stick in the same position all the time, not that I'm doing anything weird with it.

Sometimes it happens when the terrain I'm on it's not totally flat, but I think it happens in other situations as well. Any ideas of why this is happening? I repeat, it NEVER happens in multiplayer mode with the same controller and same configuration.