Car glass problem

[Taycan]

I added a rear spoiler to the bmw m4,but the glasses have been blurred out.

before:

after:

I don't know why.
If someone have a few minutes to help me.
Thank you guys.

 

[Stereo]

The glass material got changed, can't really say much about that without knowing how you switched the wing.

 

[Taycan]

The glass material got changed, can't really say much about that without knowing how you switched the wing.

Thanks your reply.
I found the problem is when I export new kn5,the glasses got changed like this.
It has nothing with the wing.