How to set a mob to only attack when target is in water

Hello, i would like to make my water mob attack only when its target is in the water, i have made the procedure:

Return: Is (Get entity [Event entity] is targeting) in water?

and set it to the additional start and continuation conditions in the Mob AI tab, now when the procedure is set on the start condition it crashes the game, but when it is set to only the continuation condition, my mob attacks me outside of the water anyways? any help is appreciated :/