Game Mechanics: Mob flee

[BABSIE]

Often when a mob starts to flee it gets "stuck" in the turn animation and, er, "slides" across the ground. It gets stuck in a weird loop in which the mob moves forward, warps backward but 2 feet or whatever away, and repeats for a few cycles. During this time you can't hit it and eventually it resets w/ a new turn and pops 10 feet or whatever away. Hard to reproduce, at first I thought it was the result of fighting on hills, but tonight it happened 3 times on flat ground.