Two Monitors automatically changing contrast/brightness

[Ueberaktion]

So, i have a problem. Based on the content on my screen, the brightness/contrast of the picture changes automatically. Since i have one Benq and one Dell Monitor, it´s quite unrealistic that this is some kind of a monitor or display driver setting. I´m not quite sure when this started and haven´t found a solution yet. I saw other people having the same problem, but nobody seems to have found a solution. I tried changing the windows power setting - nothing, and when i tried to uncheck the Adaptive Brightness Box inside the Nvidia Driver, i noticed, that I don´t have the option either. I also checked for weird programs inside task manager and didn´t find anything suspicious.. This is really really annoying and I hope somebody can help me. -Greetings from Berlin, Germany

Specs: i5 7600K, MSI Z270 Gaming-Pro Carbon, KFA2 NVIDIA GEFORCE GTX1060.