Still the same after a factory reset?
Report the fault with staff on live chat, just make sure to click “chat online”.
Wow, I see what you mean by pixelated 😢
I did see the green/black thing on our LG GX, when it was cycling through the artwork in the screensaver; one picture, once, turned green halfway down, and this persisted until the next painting came up. And when the affected painting came round again, it was fine.
So it does look like the green/black is something LG sets can do when they glitch. But I have seen nothing like that pixelation.