Falling through the enviroment

this is my second time falling through the environment, both happen to be when I was using the vault skill on upper levels in the cathedral. I snagged the one screenshot accidentally going over another one.

http://imageshack.us/photo/my-images/545/fallenthroughfloor.png/

also I keep noticing while using evasive fire within 10yards of an enemy around destroyable objects, ie, tomb stones, barrels, ash jars etc I tend to get stuck and my only way out is if i have vault on my bar or if I am able to evade from another mob.

I've not been able to get the barbarian stuck in any of the debris, or walls or anything as of yet.. but I'm trying pretty hard