I already ordered Walmart for a replacement of my Samsung Q80R because of vertical banding which is visible when watching soccer games, on gray uniformity test and gray menu pages.
The attached image shows it but the real life situation is slightly worse.
If this happens to the replaced TV too, what to do next?
Let me start by saying I'm an audio guy, not a TV guy, so take this for what its worth.
I bought one of these two weeks ago(the 82"). Out of the box, I saw some faint vertical banding on an all white screen, no other color. I made a number of changes to the picture settings which reduced the visibility of the bands to the point where I can't see them even when panning across a white hockey rink, so I'm good with it. I made the changes not to specifically address the banding, just to improve the picture in general. I suspect reducing the backlight a bit and turning off contrast enhancer had the most effect on minimizing the banding but I don't know for sure.
What this all says to me is that you should not have to live with DSE/banding you notice watching regular content. What I would do with a new unit is adjust the picture settings to your taste and go from there. I would not make any return decisions based on something you only see faintly on an all gray/white screen, or test patterns, that is not a problem watching your normal content.