I dont quite understand what you are describing. Did you glitch into the tractor model or did the tractor simply stop being able to move. If you glitched into the model which would result in you getting stuck then yes that was a bug but if the tractor just wouldnt move forcing you to exit into oncoming fire it would seem that a critical part of the tractor was damaged beyond use as to render the tractor immobile untill repaired with the proper item depending on the specific part/parts damaged.