Vel'Koz ult crashing game.

Playing an ARAM match with a friend who was on Vel'koz. Half the times he ulted the game would crash... almost everyone in the lobby. Didn't happen every time so I can't quite say what the cause was, but the champ list was Our team; Teemo Maokai Evelynn Vel'koz J4

Their team; Garen Malzahar Anivia Urgot Karthus

As I said, it didn't crash every time he ulted, so I would imagine Vel'Koz ult + ? = crash. Anyone else had this happen?