But why is there a subspace whirl appearing every time one of these meteors shows up?
That's just an oversight with the testing envoirment:
You see the "meteor" is actually just a missile covered in particle effects, so to control when it is spawned via weapon-create
I set the events condition to a has-arrived-delay
of a reinforcement ship, the ship then get ship-vanish
'ed but I keep forgetting setting the No Warp Effect-flag on arrival.