I noticed that when you set Windows Update on Windows 2012 R2 Server on "install updates automatically" it do install updates but do not reboot server. When you connect to server you get a warning that "server will be rebooed within 2 days, 1 days, today ect.." but no automatic server reboot.
Today it rebooted at mid-day when many persons where connected !!!!!
Any idea of this problem?