This happened with an Amazon character when running over campfires that are on the ground in the corridors of World Stone Keep. The character gets stuck and can’t move away from the middle point of the campfire. I could reproduce this effect with the same campfire multiple times.
I’ve remember getting stuck too, but for me it was in some dungeons in A2 (halls of the dead probably). I had to go to town via portal to “unstuck” myself.