WSUS 3.2.7600.226 running on Windows Server 2008 R2 VM, Active Directory 2008 R2 environment. Using GPO to configure client servers in the following manner:

Configure Automatic Updates - 4 - Auto Download and schedule install

Scheduled Install day - 7 - Every Saturday

Scheduled insall time - 02:00

Specifiy intranet Microsoft update service location - Set to internal WSUS server

I had been noticing recently that Server 2012 machines would install but not reboot automatically at the install day/time (3 day countdown deal) so at first I edited local group policies for "Always automatically restart at the scheduled time". I then imported the latest Windows8.1/Server2012 admx/adml files on the domain controller that I mange group policies from and added "Always restart at the scheduled time" with a 15 minute countdown via GPO. On Friday (9/11) I approved critical September 2015 updates for my development and test servers (Server 2008 R2, Server 2012, Server 2012 R2) set to install on 9/12 @2am. This afternoon while checking on the status of the updates I noticed that every Server 2012 R2 system downloaded the approved updates via WSUS but they did not install/reboot according to the GPO (they did not install at all). My 2008 R2 and 2012 Non R2 systems behaved as expected on 9/12. What I am now wondering is if there is some bad interaction between the GPO settings and the "automatic maintenance" tasks that exist in the task scheduler on these Server 2012 R2 systems? On the systems that downloaded but did not install I notice that the Tasks under "Microsoft - Windows - WindowsUpdate" are as follows:

AUFirmwareInstall - Disabled

AUScheduledInstall - Ready - Next run time 9/19/2015 2:00am (seems to jive with the GPO but why did it miss 9/12?)

AUSessionConnect - Disabled

I have 1 Server 2012 R2 system that did behave as expected (installed updates on 9/12 @2am) and the only difference I can find with this server is with the AU tasks:

AUFirmwareInstall - Disabled

AUScheduledInstall - Disabled - Last ran successfully 9/12 @2:00:34am

AUSessionConnect - Disabled

How are these tasks controlled outside of manually configuring them on each server? It seems there may be some interaction with GPO but I am unsure of how/where? Any help/advice is greatly appreciated.