I experience the same issue. The bottom left side from now two TVs for Costco have raised black level issues. Just like a LED backlight issue. That’s ironic right? I have yet to find a fix. It does seem specifically it is noticeable when viewing Dolby vision content. Interesting nobody has posted about this in this site. One of the biggest issues and completely destroys the purpose of OLED TVs. When I seemed help and had lg techs come out and look they laughed at me. Fantastic tv world we live in.