@kurata I think I found the issue. For whatever reason when you go fullscreen, it's like you're going into a new screen where the brightness is different. Just change the brightness level while in full screen and it works. At least it did for me.
Posts made by imagine-simping
RE: Fullscreen BrightnessOpera GX
Fullscreen BrightnessOpera GX
For whatever reason, whenever I go fullscreen on YouTube, my screen's brightness goes up 10 fold. I tried updating my drivers, changing display settings, and changing Opera settings. This is only happening on Opera GX, and has been going on since I updated it about 2-3 months ago.