This was true in the original Model S/X, because a screen that size didn’t exist in automotive grade. They resorted to using an industrial grade screen which they qualified for use in the car, but it’s had the yellowing issue.
My understanding is all the new screens are tested to Grade 2 instead of Grade 4 like the original screens from Innolux.
The article doesn't say it's now a grade 2 screen. The article does quote Mentor Graphics saying, "defining the boundary conditions for Innolux’s system is the responsibility of their customer, not Innolux."
So Innolux will quite happily sell Tesla a screen, but it's up to Tesla to use it appropriately. I think your understanding is wrong.
Not really. The robustness of the screens in Teslas is particularly poor:
https://www.thedrive.com/tech/27989/teslas-screen-saga-shows...
Tesla didn't go with automotive grade screens which is why the screen failure rate is so high.