That seems to be a new feature in windows 10, if you go to windows update itself it might also say "Some settings are managed by your organisation" at top, even if its your PC.
this happens if you have active hours set and run the update in a time you have allocated as your time to use PC in. I know as it has happened to me on the last 2 Cumulative updates on 2 different computers here.
The simple answer is to run windows update from settings/update & security/windows update. It will restart PC and after a while the warning about Settings being managed by organisation will disappear and PC won't want to install anything on shutdown or restart.
You can't turn off active hours, so best idea is just either change them or only run...