Why is my key light not switching off when battery saver is turned on?

[Windows Central Question]

My phone is running WP 8.1
UK version with O2 as the carrier.

 

[dKp1977]

Are you referring to the backlight of the touch buttons on the bottom? Are they even supposed to be disabled with battery saver turned on? Oo

 

[Joe920]

Apparently this is a bug in 8.1 related to opening Device Hub. If you do this once, there is no fix other than a complete os reinstall.