[Ace]

Why are you using Casting Target? Casting Target chooses the target that your target is casting a spell on, meant specifically to be used in situations where you are targeting a boss or other enemy that is casting another spell on a tank. Casting Target would in turn use the tank that is having the spell cast on it as the target.

Looking at the code, it's probably only by accident that it happens to work on target dummies since they are never casting and some of the abilities allow casting on a target ID of 0.