For the last update installed date, I'm looking at Control Panel, All Control Panel Items, Windows Update.
For last update shown, I'm looking at Control Panel, All Control Panel Items, Programs and Features, Installed Updates.
The only theory I can come up with is, the other day, I attempted to uninstall the 8/14 KB2975719. It appeared to be stuck near the end of the progress bar, and it was getting late, so I clicked on Cancel. Maybe, somehow, the uninstall completed the next time I turned on the tablet, and caused the Updating message when I did a restart the other day. I noticed that after installing the new KB2975719, the one from 8/14 was gone from the Installed Updates list. Unfortunately, I didn't notice if it was gone before I did the installation.
I've also found that the other two updates that I found installed when I Installed the new KB2975719, were part of the KB2975719 update. Ref -
Download Update for Windows Server 2012 R2 (KB2975719) from Official Microsoft Download Center That article said I would be prompted to select the files I needed, but I wasn't prompted for anything.