Can not edit / configure vehicles

Hello
Whenever i try to edit / configure a vehicle, it does not apply the added modification to the car.

For example, if i try to add a different bumper, the bumper on the car will become invisible. When i close the vehicle configuration menu and navigate back to the bumpers, the bumper will return to stock form. I am able to tune vehicles, but not swap parts. This goes for all vehicles and all parts

I have tried reinstalling the game and deleting all mods, none has worked.

Any thoughts?