I have investigated this issue with over 50 note 8s at different carriers and stores verzion Best buy at@t Sprint TMobile coorporate and authorised resellers and uscellular I work there and see note 8s all day a few devices might have delamination issue causing the waterproofing to be affected maybe 0.07 percent of devices. The main issue with the light bleed , refraction or whatever you want to call it is with the black coating under the glass border not Completely meeting the frame and yes temp can affect this but not much my note 8 is perfect but the first 3 I had to return and Samsung admitted that this is a issue that they are supposed to be addressing which I think they are cause newer units produced seem to have no light issues.
Just glad my 4th note 8 is perfect no illusion issues we will now call it lol. The phone is beautiful and a joy to use. Would not go through 3 returns if not a dedicated Samsung fan.