I know it's no big deal but the cursed skull tries to spawn the monsters on the tiny zeppelin but it can't find ground so it generates them on the soil 20 blocks below but it'S too far from the cursed skull so it de-activate when going down to kill the monsters so when you go back up you have to reactivate it but it's still lacking ground to spawn the monsters so it'S an endless loop of failure.
I know, I understand that it's just a 2 weeks event and that no cursed skull will be generated on zeppelins afterwards, but IDK, paying attention to details beforehand and testing new creations before calling it a done job is kind of the best practice in everything.