I’m not 100% when this started, but I first noticed it with the recent release of the August 2014 Cumulative Update (CU) and the August 2014 Public Update (PU).  Running Windows Update, the SharePoint 2013 PUs show up and are available for download and installation.  In the screenshot below, SharePoint 2013 Public Updates were released on August 12 the  August CUs (note: some of the patches shown in the screenshot below were released in July).

SharePoint 2013 August 2014 Public Updates

Once these updates have been installed, like all SharePoint updates, you must run the configuration wizard.  After running the configuration wizard you can check the build number in one of two ways.  Either going to “Servers in Farm” and viewing the version there or you can open up the SharePoint Management Shell and run (Get-SPFarm).BuildVersion.  You’ll notice that both methods show a build version of 15.0.4641.1000.  However, the August 2014 CU has NOT been installed.  On the other hand, if you install the CUs before installing the PUs, you’ll have the same results.

Build Number in GUI

Build Number in PowerShell

So, if you’re looking at a farm for the first time or you weren’t the ones to install the patches, how do you know what your patch level is?  How do you know if the CU or PU, or just part of the CU or PU has been installed?  It appears that know you have to resort to looking through the Product and Patch Installation Status to look at each component to find what KBs have been installed.

Patch Statuts

Part of the patch Installation Status Page after just the PUs were installed.
SharePoint 2013 August 2014 Public Updates

Part of the Patch Installation Status Page after both the PUs and CUs have been installed.
SharePoint 2013 August 2014 Public Updates and Cumulative Updates

If anyone has a better way to find exactly what patches, CUs and PUs have been installed, let me know below in the comments!