It's to do with the [URL="http://answers.microsoft.com/en-us/surface/forum/surfpro3-surfdrivers/surface-pro-3-with-lgc-lgc-battery-degradation/f4fc3ec9-0771-46a3-8282-eaf588a7457e]LGC battery problem[/URL]. The controller has been misreporting the battery charge and this update was supposed to fix it. Unfortunately, some people have found that it makes no difference.