Default [Q] Power button issue

Hello.
I removed the back cover to clear my tablet from dust, and when I assembled the device I found that power button had become lower in cover's body than volume buttons are, and now it has worse push feedback (less significant click and no click at all when I press it near to its edge). Taking cover off and back on changed nothing. Have I done something wrong and break or lose something while putting the cover back on the device?