I’d suspect it’s just the AI doing its thing. My original source is the bluray release 😃.
In my recolor, I do bump up the contrast a touch. With this visual change, and knowing that the AI upscaling processes is not a one for one, I think that explains the variance.
Your screenshot is also a weird resolution 2300x1292 which is likely messing with the image quality 😃. The actual resolution of the 4K release is 3840x2160,16:9 aspect ratio.