Galago Pro keyboard backlight settings slider has no effect

[josephdickson]

NAME="Pop!_OS"
VERSION="18.10"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Pop!_OS 18.10"
VERSION_ID="18.10"
HOME_URL="https://system76.com/pop"
SUPPORT_URL="http://support.system76.com"
BUG_REPORT_URL="https://github.com/pop-os/pop/issues"
PRIVACY_POLICY_URL="https://system76.com/privacy"
VERSION_CODENAME=cosmic
UBUNTU_CODENAME=cosmic

Computer: System76 Galago Pro (Galp3)
Bios Release Date: 03/26/2018

On my system dragging the keyboard backlight slider has no effect on the keyboard's backlight. However, Fn +F4 which is the key combination works just fine for stepping through the keyboard backlght levels.

To reproduce:
Test the power settings for the keyboard backlight on a third generation Galago Pro.