Immediately after this happened, I called down another Bestowing Ceremony that was actually interrupted by a social fight starting between one of the guards and the bestower himself, but when they finished nobody was downed. Instead of boarding the shuttle they all wandered off the map instead, leaving the empty shuttle behind
I do have Harmony, Won hair_women, Won hair_men, and Pick Up and Haul mods installed but they probably don't have anything to do with this.
Update: Once all of the people in the original shuttle starved, they all got kicked out of the shuttle and the Royalty empire full on declared war on me- and the people in the second shuttle who hadn't made it off of the map yet became hostile and turned around- but instead of actually attacking my colonists, they ONLY THEN ran to and boarded their shuttle.