Windows 10 October [1809] Upgrade

HeM said:

That's it. Your DVD has 1709 (Sep 2017) installer.

And, @Jungee, maybe you misread your version as 1809 instead of 1709? It would be perfectly normal for 1709 to upgrade to 1803. I've never heard of any version automatically downgrading to the previous version - ESPECIALLY if that previous version was never installed to begin with. Downgrades to the previous edition initiated by the user rely upon the files contained in the Windows.old folder and a new install would not create a Windows.old folder.

You clearly installed 1709, because windows doesn't do downgrades automatically, and only does so manually if windows.old is available