This was a strange patch Tuesday. First a regular cumulative update KB4524570 to 1903 was installed. You had to check for updates a second time to get the invitation to download and install 1909. The 1909 upgrade barely took any time to install - maybe 10 minutes. Once it's installed, System / About says it's Version 1909, installed on 5/30/2019 (the date of installing 1903), OS Build 18363.476 . Update history shows both 1903 and 1909. It really looks like MS it treating 1909 as a minor update.