I have two Note 8, and one of them suddenly became too bright. I use dark mode and the black is no longer black, its a dark shade of gray. But its not just it, everything is bright, if I open the camera it seems brighter. The icons are bright. Even the display settings at all options (adaptative, amoled cinema, amoled photo or basic) have the test picture too bright (no true black). Literally everything on the phone is brighter.
If I reduce brightness to minimum, and disable adaptative brightness, no true black either.
HOWEVER, the boot screen have true black, and if I download a black theme, the areas the theme controls have true black background. I also noticed that when on white blackground, the black of the fonts are not true black (dark grey).
My other phone with the exact same software and configurations work fine. Only one of the phones have this issue.
The weird, as mentioned, is that any software that shows a true black (#000000) color, displays it correctly. It is as if the UI is no longer accepting black as a valid color or something and, as I mentioned, the camera app also displays images brighter than they are, even at minimum brightness, its really annoying.
Seems a software issue but no UI setting other than a theme (which doesn't fix icons, camera or apps that don't use the theme) works. Oh, and if I leave the default theme and turn dark/night mode on apps that have it, like youtube, backgrounds also go to dark grey, not black!
I took a screenshot and sent to my PC, and the back is true black (#000000), now I am trully lost as to what is going on!
I tried Safe mode to no avail. Trying a factory reset now...
FACTORY RESET SOLVED IT. Who knows what corrupted/got corrupted to get to that state =/
Yes, he says factory reset fixed it. I'm facing a very similar issue on my Galaxy S9 since a few days ago. I will try factory resetting as well and I hope it will help.