It happens on all maps I've tested on regardless of character used, but sometimes randomly fixes for certain periods of time before going back into a weird skipping loop. No monsters are affected by this, just the player character. I'm not terribly concerned about it, just thought I'd see if anyone knew anything about it.
(It's just the animation, movement is fine)
* edit - What's odd is that nothing has changed since I last played this game, I keep my settings relatively the same, and play on the same drivers. So I really don't know what could be causing this. Guess I'll just live with it.
* edit again just for note, when I had the Holy Shield powerup, everytime I moved the sound effect would also reset with the character animation. I thought maybe the mouse I'm using was causing issues, however this doesn't seem to be the case either...no idea.