Problem not in decorator, but, as I think, in MoveTo task. Once controller gets valid MoveTo location, it starts to execute until character reaches it. Only after that whole branch is restarted, controller gets new MoveTo location, and executes it again.
This works if AI character gets enemy location who stands on the same place. But if enemy location is changes continuously (so player trying to escape from this ai character), this not work. Ai character always stops in some intermediate locations while chasing his enemy.