Keyboard backlight setting does not stick after reboot

[TheUninvited]

Keyboard backlight gets unticked every reboot.

Before reboot, I tick it and select any timeout I want.

After reboot, it gets unticked.

Tried deleting the following in ~/Library/Preferences but same issue after reboot.
1. com.apple.systempreferences.plist
2. com.apple.HIToolbox.plist

Any advice?

Using the latest High Sierra beta (17A352a) on 13" NTB MBP late 2016.