Latitude 5420

What specific Windows Update caused the audio issues that resulted in the release of "Realtek High Definition Audio Driver" version "6.0.9418.1, A18" for the Latitude 5420's?

The Driver "Fixes and Enhancements" states: "- Fixed the issue where there is no sound from the speaker when only partial driver is updated through the Windows update." With no further information about what specific Windows Update caused the issue. Does anyone happen to know what specific Windows Update this is referring to?