this happens from time to time when a car hit something (another car, rock, tree) at high speed. when it happens, one or two tires from same side can get under the surface of ground. player and AI can still get in/out the car but only be able to move the car slowly. sometimes, you may get it back onto the ground by hitting it using another car.
if the tire is damaged and rim trapped under the ground, I, as a commander, don't have fix option in the action menu of engineer soldier on my team.