When viewing computers that have recently upgraded to Windows 10 version 21H1, you notice that the console does not show the correct version. In most cases, it shows 2009 as the version.
ITMS 8.6
Microsoft stopped updating the ReleaseID property that ITMS used to detect the version to display in Console.
Support for Windows 10 21H1 was added to 8.6 RU1 as seen in the documentation link below: