Beware - Known Issues with update 

kb3159398

Breaking of Security Filtering with GPO

Has anyone had issues with this?  It's a GPO security update:

https://support.microsoft.com/en-us/kb/3159398

But there are reports of it breaking GPOs.

https://community.spiceworks.com/topic/post/5913659

https://social.technet.microsoft.com/Forums/en-US/e2ebead9-b30d-4789-a151-5c7783dbbe34/patch-tuesday...

EDIT:  MS has said this is BY DESIGN and thus will not be fixed.  This link explains why this is happening and how to fix your GPOs so you can apply this update without issue.

https://support.microsoft.com/en-us/kb/3163622

Don't want to read the whole MS article?  See this post, later in this thread:

https://community.spiceworks.com/topic/post/5917169

EDIT 2:  I strongly urge everyone to NOT decline this update.  Don't approve it, either.  Check all your GPOs, fix them if needed, then approve this.  This is a needed security update and just declining it is not a good idea.  I'm sure later updates will be based on this one.

ref: https://community.spiceworks.com/topic/1666296-beware-known-issues-with-update-kb3159398