Server gets updates and reboots in the middle of the day.
(h/t Michelle T link)
Allow configuration of Automatic Updates in Windows 8 and Windows Server 2012
However, the scheduled day and time in this policy setting has no effect. The computer still installs downloaded updates during automatic maintenance, which defaults to 2:00 AM. Additionally, the computer no longer restarts 15 minutes after installing updates. To help avoid unintended data loss, a restart timer instead begins 3 days after updates are installed, and only when you are actively using the computer and are able to see and react to the restart timer.
An update is available that lets you control how the Automatic Updates client applies updates in Windows 8 and Windows Server 2012. After you install this update, the “Configure Automatic Updates” policy setting will work again as it used to in previous Windows operating systems. Instead of installing updates during the daily maintenance cycle, Windows updates will be installed at the time and day that are scheduled in the “Configure automatic updates” policy setting.
This update also introduces the following Group Policy setting that you can configure to force the computer to automatically restart sooner in order to finish installing important updates:
To obtain this update, install update rollup 2883201. For more information about how to obtain this update rollup package, click the following article number to view the article in the Microsoft Knowledge Base: