Power Button strange issue

Hello everyone,

Resently i changed the screen in my 8 plus device. Since then, the power button has some strange issues. First of all the click works well always and the phone locks. But the long press function doesnt work so i can’t power off / power on the device. If the screen is off and try to longpress, it comes alive but the “slide to power off” doesnt appear. The volume buttons are working perfectly.

I tried hard reset but didn’t help. The flex cable don;t have any damage as far as i can see.

Another problem after the screen replacement is that when i am making a call or when i try to use the camera, the phone always restarts.

Any ideas what might be the problem?

Thank you