Hi! I've been unable to consistently use the system's shutdown shortcut after upgrading to Sierra. I followed @oa-'s instructions here, which temporarily fixed the problem:
http://apple.stackexchange.com/questions/253968/macos-sierra-how-do-you-enable-shutdown-keyboard-shortcut-ctrl-opt-cmd-p/253978#253978
…but the shortcut stopped working again, and repeating those steps again didn't fix it this time. Can anyone advise me on further steps I can take to identify the root of the problem, and solve it in a more robust way?