Not a problem or something that should be fixed, and made intentionally.
When a parking is selected, ALL vehicles that you *might* need are placed in the parking spot area, and they also move into position, even if you haven't called their services, so we minimize the chance of vehicles arriving from far away ( fuel truck and catering ) to run into the vehicles that start at the parking spot, so we move them to their position at the airplane doors, so it will be very unlikely they'll clash with the arriving vehicles.
