Not Sure wtf is up

while doing a council run with my zealot the graphics went all screwy
it did this again on a hell baal run when the hydras appear
exactly what happened was all the characters, monsters, and effects flashed in and out
then completely vanished for a few seconds, just log enough to die from not being able to find a monster to lock on to

items will still appear on the ground when i hold alt during the glitch but it does cause a problem when
zealing in a mob that tends to run around allot

not sure if this is some glitch in the game or a problem with my own rig but i have never seen this happen before

anyone else have this problem?