Spell interupt bug(I think)
 

It is /really/ hard to cast spells when levitated now, since you bob up and down. I know it was not this way on live before(Done it since beta 3 till Kunark release), but they might have changed it. You could just have it ignore Z movement of 3-4 feet(whatever), while levitated.

i think z changes is ignored totally or large amount of feet ( or til you start to panic and wiggle over while falling ) before casting is irreupted. i have sucessfully cast while falling before. most falls is like from running over cliffs etc so x and y is also changing so spells wont work.