When a user logs off during a valid scheduled 'update system settings' message, the restart is postponed until the next user logs on.
A permanent fix has been provided in 7.1 SP2 MP1 V4.
A point fix is available via Symantec Support for this behavior.
CHANGES MADE Fixed logic in restart notification such that logoff/shutdown are handled as if the restart now button is pressed. i.e. if the user logs off when restart notification is shown it means we have administrators approval.
NOTE: The attached Point-fix should be run on the Notification Server. This is only for version SP2 v4, where the final fix will be in 7.5. To install, extract to the Notification Server and run the PFInstaller logged on locally as the Service Account.