I'm not sure when this started because it used to work, but when I add a Keyboard Illumunition Up or Keyboard Illumunition Down action to any Keyboard Shortcut, nothing happens. They work fine if I click the "Run Action Sequence" and they do work fine with the trackpad.
I'm on Sonoma 14.6.1.
EDIT: A delay of .3 seconds solves the problem