Viktor Gravity Field not stunning if placed on terrain.
There is currently a bug that prevents the stun from Gravity Field activating so long as Viktor has evolved the ability and the center of Gravity Field is placed within impassable terrain. (Not tested with player created terrain) Instead of stunning, the slow is constantly refreshed and stays at 3 stacks. https://www.youtube.com/watch?v=1zsEAHkscvQ