Like the OP, kept getting the update message every day.
"When you did the update, did you reboot immediately after as instructed? "
Uh, it does not "instruct" that. The message box says Your computer must be rebooted in order to complete the installation. Would you like to reboot your system now?
Politely implies a choice to reboot when convenient. If that's not the case, the message should say "YOU MUST REBOOT RIGHT NOW or you will continue to get update messages"