I like Paul Thurrott's explanation and not only because of the unambiguous headline:

https://www.thurrott.com/windows/windows-10/4257/guys-seriou...

This makes it sound like current insiders who previously ran Windows 8 but did a clean install from technical preview iso will be required to reinstall with Windows 8 and then upgrade again in order to stay genuine?

That can't possibly be right, can it?