My odissey with XPS 15 9550

Hello,
I bought the XPS 15 in April and from the start it has  been an odyssey. The problem is the screen, I have a band of 5 mm on the right side that is with some brighter colors of the rest of the panel. I noticed it watching the football matches at full screen, with green field is very noticeable. After this discovery I noticed that you could see it with some wallpaperthat before i hadn't noticed. I called the Customer service, they have replaced the panel and nothing has changed, then they have replaced the motherboard and nothing changed too. I noticed that it is more evident with middle tone colors, not bright, not too dark. I started  my test with the green of the field that i discovered that it happens with purple, red and of course with gray.  Then they replaced my pc and nothing, I see still the *** light stripe on the right side. At this point I don't know what to think, maybe it is a normal phenomenon for this type of panel . Please tell me, do you have it too? I want to understand if I have to keep this second PC or return
I enclose a photo taken with a cell phone of the problem, even if it is more evident with movies.