When you see the cycling of livery/aircraft type bug at a single gate you get lots of ‘Parked at {airport} as unassigned’, it repeats and repeats as it goes through endless cycles. Had this bug show at KBUR tonight. The injector shows the ‘unassigned’ message as it spawns them, it must mean something.
EDIT: OK suggestion from devs discord is this is happening because of gates being too busy, so set ‘additional parked aircraft’ in the injector to ‘1’. Something to try if you are seeing this happen.