The way my vehicle mods are setup: I go to the DLC folder "Mpluxe" and add totally new cars. For example, to create a new car I'll take the vehicle files for say a new crown vic, rename them something like "LAPD1", and import them into the "mpluxe" folder. Then I go to the carvariations.meta and vehicles.meta files and then create a new vehicle there. Before the update I could spawn in these new cars no problem. After the update when I try to spawn them, they just don't appear at all. Anyone else having this problem? Is there any way to fix it?

I'm not sure how to fix your problem but I'd just like to confirm that add-on vehicles are still possible. :)

I have the same Problem here, extra cars are not working anymore. The game crashs at startup.