Confirmed and logged, awaiting fix. Moved to confirmed bugs.
It's not really a bug, more of a quirk of how the spawn system works currently. There needs to be some situations where it doesn't spawn your car again, but rather keeps it spawned already (or vice-versa) lol. Its annoying when you spawn in an interior to have it attempt to spawn your car too, so that needs to be fixed as well.
If you don't want your car to be re-summoned upon coming back just turn off the auto-summon feature in /settings. Then your car will stay spawned while you are away.