I purchased my Q9FN a couple weeks ago (AA01 panel) and it has a couple dead pixels, significant vertical banding as well as DSE while watching hockey, other sports or scenes with solid colors and motion

In speaking with the technician when he was here, he said there needs to be more than 1 dead pixel in order to perform service

Even with the second dead/stuck pixel it was turned down for repair again by Samsung

He agrees that there is indeed a dead pixel in the center of the screen as well as uniformity issues creating a dirty screen effect

Upon further inspection, after the technician left, I found a 2nd dead pixel not far from the first one

It had 5 dead pixels spread around the edges of the TV and a bit too much DSE on light backgrounds.

Sure enough there were still dead pixels on the new panel too: one on the right side by the edge of the panel and another large one on the bottom middle area