when event getting started u order the unit to attack a a region. this is an order, too, so the trigger keeps ordering again, and again... the trigger is always activated >> crash u know what i want to say?
infinite loops are usually instantly recognized by warcraft and shut down. However, this is not a loop, it is a trigger which triggers itself, and programs tend to assume you wont make that bad of a mistake... like trying to get Player(-1) lolz