It seems like Grand Theft Auto V has been hit by a nasty Vehicle bug because of which gamers are loosing their cars and also some of their upgrades.
Rockstar Games via their official support page has stated that they are very much aware of the issue and are looking into it.
Here is what Rockstar Games wrote on their support page:
Question: I upgraded my car and then completed a mission, and now my car is gone. Help!
Question: I’ve lost some of my upgrades after completing some missions and then checking my garage. What should I do?
Answer: We have received some reports about problems with cars and garages, particularly after upgrading and then completing a mission, and are looking into this now. If you would like to receive an automatic email notification as soon as there is more information, please log into the Support Site and click Subscribe at the top of this page.
How you encounter vehicle bug in GTA V?, let us know in the comment section below?.