We have a issues with one D735 which is quite new, and was working perfectly fine.

Suddenly it now only have a empty screen with no information and buttons are all lit up.

When doing a "hard" reboot (unplugging and plugging it in) it shows in the display it's name D735 and after a few seconds it goes dark and all buttons around display are lit up.

Any idea what causes this? Difficult to see the image attached.