Photoshop is making my monitor brighter

[Sportimer74]

Hello,

Without touching anything, CC 2018 is making my screen lighter and with gradient artifacts. A few seconds after closing, problem disappears.
I updated graphics card driver, CC 2018, and recaibrated my monitor and tried disabling GPU just in case. Still nothing, can anyone please help? BTW, Lightroom is running fine.

Thanks.

Enrico.