Ok . What am i looking for on test screens? If they look fine what does it indicate. Sorry for my ignorance.
Source video compression can introduce gradients
But so can TV itself depends on how good processing is, even with high bitrate I've seen this on BD planet earth, maybe one scene per episode
It's not faulty. you're giving it poor quality content, so it's showing you poor quality content
So if it does show posterisation is the tv faulty?
Not necessarily. If you have 1080p and 4k bd and it shows on every single movie constantly, it could be the TV or some settings. Ie if I force 8 bit from the source and your TV is 10 bit..or some kind of contrast enhancing feature you have to max. Or it could simply be the disc.
I believe game of thrones on subscription season 8 suffered from really bad postersation.
You need to view that YouTube video, if it looks ok then you know screen uniformity is ok (or led backlight of its LCD) so then it would be something else .