Windows 10: Why brightness change when fullscreen game?

I noticed the brightness increasing a lot when playing some games fullscreen.I noticed this for dota 2 and black desert online. I played these 2 on steam on my lenovo windows 11 laptop.I did not see any brightness settings under windows system or the game settings that might cause this. I used the brightness increase and decrease function on the keyboard to adjust the brightness, but I prefer knowing what causes this.

:)

 

Windows changes any fullscreen to maximum brightness

Hello,

my Windows Notebook made some Updates yesterday and today it changes the display brightness to maximum whenever a programm in fullscreen comes into focus. This applies to videos (VLC/Mediaplayer) as well as my browser (Youtube-videos and so on) and games.
Brightness can be reduced when program is in focus and stays adjusted until any fullscreen is in focus again, even the same program. Updates and System Drivers are up to date. Automatic adaptive brightness adjustment (or how the option is called in english)
is completely disabled. Any ideas on what can be the reason for this pain in the eyes?

 

weird lighting with non windowed Fullscreen programs that have a black background (may be bug with adaptive brightness)

whenever I open a Fullscreen program with a black background it instantly sets my screen brightness to zero, while displaying the value as 100, if i alt tab out of the program it will persist until I make any change to the system brightness, however it will re occur when I move back to the program, i turned off adaptive brightness and it did not change, as well as adjust game mode settings as the guide I tried suggested, but nothing has worked so far, has anyone had this issue before and if so what should I do to fix it?

 

How to verify Fullscreen Optimizations feature is off?!

In one of my games it doesn't happen at all. But I can force it to happen in this game by setting gsync to "fullscreen and windowed mode". Once I change the gsync options to fullscreen only the brightness fluctuations stop. But this fix doesn't work in my other games. The game that it's fixed in is dx11 while other games that still have brightness fluctuations are dx11 and dx12. But something tells me that it's a Windows issue as it doesn't happen in one game.