After a time playing, the cars lose the exterior of the chasis

For some reason, after a few minutes of gameplay the vehicles that I have installed (mods) will loose part of the chassis:

Whops

Just in case, this is how the car should be:

My sister says that this is kawaii

I installed a few car mods, but the one on the picture if this one.

What is the cause of this bug/glitch?

If more information is required, I have no problem on showing it.

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