What's the matter with the grey buttons on oppo phones?

Hardware damage, keyboard line problem.

1, eliminate hardware damage, whether water enters, the mobile phone is dropped or squeezed. Installing software with poor compatibility leads to system abnormality.

2, worry about the keyboard cable, if the cable interface is loose, it is better to deal with it, try to tighten it, if the cable is broken, you can try to repair it with conductive silver paint.