Fourth Tuesday of Month may be a Patch Tuesday also
This may better explain the recent non-security patches last Tuesday.
Fourth Tuesday of Month may be a Patch Tuesday also
http://blogs.pcmag.com/securitywatch/2009/11/the_other_patch_tuesday_is_the.php
QUOTE: Everyone knows about Patch Tuesday on the second Tuesday of the month, but it's less-known that Microsoft regularly releases non-security updates on the 4th Tuesday of the month. You might have noticed Automatic Updates rebooting your system with several non-security updates just this Tuesday.
I dug a little more and found some references to the policy: