Blitzcrank Hook and Sion Ult Interaction

I'm not sure what the correct interaction should be but Morgana should have been hit by the Sion ult as there is no black shield or such on her. It very clearly in the video shows a blitz hook that a Sion goes directly through the morgana on the enemy team which should not have happened. Leave Your Thoughts Below!!! P.S. Sorry about the video recording in advance.