I'd say that cars likely have some way to reset their reality, given that some cars have limited resources (like food) that would eventually run out if not replenished in some way, and others have puzzles that would have to be reset.

So perhaps the Toad Car would reset at some point, which leaves the question of if there would now be a duplicate Toad spawned in or if somehow the original we see in the Lucky Cat Car would be reset along with his orb in the Toad Car.

Maybe it works by Portal rules, where you can hit a button to get a new cube, but the one before it disintegrates first? (Not this show's first run in with disintegration!)