Since the original thread linked in post #4, I have been examining my screen in a wide variety of ambient light situations.
I have nothing like the examples posted on either of the threads. If I look closely enough there is a feint grid visible but you do have to look for it. I have not seen the 'sine waves' embedded within the grids.
I've had two of us inspect my screen - today was a good opportunity for greatly varying ambient light conditions - and even when viewed from both the driver and passenger seats at differing angles, neither of us could replicate what you're seeing.
I did have a quick look at the firmware my unit is running, and it's 09.08C.00.0021 compared to yours at 0F.095.01.0021.
I have no idea if the firmware version is relevant or if adjusting your screen settings will help, but from my personal experience that is not normal.