I've already tried all processes above. I think the problem is my Intel HD Graphics driver. I tried to switch to Microsoft Basic Display driver, the problem did not happen again. And when I switch back to Intel HD Graphics driver, and I restart computer, the brightness level turn back to Suggested level (50% level)
My laptop is Lenovo G40-70. And I never face this problem before
Are you using Education CU as well? Coz many seems to face this problem particularly in this edition.
Btw, doing this fixed the problem - Potential Fix for Auto dimming in Windows 10 Creators Update • r/Windows10