Cars missing out of the blue in offline mode

Everything was fine yesterday. I exited the game normally, and the last car I used was the Lamborghini Countach. Today, I tried to continue playing via Quick Resume on Xbox. But when the game tried to load from the Quick Resume save, it crashed. After restarting, I was stuck in an endless loading screen. When I finally got back into the game, I noticed that several cars were missing from my garage in offline mode — including the Countach. They just didn’t show up anymore. I tried restarting the game, reinstalling it, and redownloading the DLCs, but nothing worked. Everything is fine when I’m online, but in offline mode, some cars are just gone. Has anyone seen this before or knows what might be causing it?