[GAMEPLAY] Casseopia's Ultimate has a wierd interaction with a Pantheon wearing Banshees Viel.
As Pantheon protected by a Banshee's Veil use W (Aegis of Zeonia) on a Casseopia who is casting her ultimate. He will not stun her - instead the Pantheon becomes glitched and cannot use skills or even autoattack again until he has disconnected from the game and reconnected. I've had this happen twice to me and was lucky enough to catch it on video the second time.
As you can see in the video the Cass isn't stunned and all I can do as Pantheon is stare menacingly at her. Intrestingly smite and movement commands still worked. Disconnecting from the game and reconnecting fixes this.