Microsoft has just updated the following KB Article:
Using log files to track the software update deployment process in System Center 2012 Configuration Manager
Summary
When you deploy software updates in System Center 2012 Configuration Manager (ConfigMgr 2012 or ConfigMgr 2012 R2), you typically add the updates to a software update group and then deploy the software update group to clients. When you create the deployment, the update policy is sent to client computers, and the update content files are downloaded from a distribution point to the local cache on the client computer. The updates are then available for installation on the client. In the “More Information” section, we examine this process in detail and show how the process can be tracked by using log files. This information may be helpful when you’re trying to identify and resolve problems in the software update process.