After landing at PAJN today, I was taxiing and all of a sudden one of the Alaska 737's just poppped into a parking spot with any landing procedure or anything. It was just there. I thought maybe there was a problem with parking spaces but the airport was pretty empty and then a little bit later another 737 came in on normal approach and landed perfectly then taxiied to its spot. What makes AI just appear?

1 - After three missed approachs on landing - the aircraft will be deleted from the session and be generated at the gate on the next cycle in 4 to 7 minutes2 - Not enough eempty parking for the aircraft - in this case an AI aircraft is usually generated in the parking spot just as the previous aircraft is pushed back3 - A timing error in the flight plan caused by using too high a cruise speed for the aircraft and a forced arrival time.If the aircraft which did the pop-up is the same model as the one which did the normal landing - I'd say reason 1 was the cause.