sudden demand for activation

Greetings
I upgraded from Windows 7 Ultimate (bought in Microsoft store) to Windows 10 Pro two years ago, on July 18 2016. This was almost the last moment for free upgrade.
Everything was OK until last updates: KB4465663 & KB4467702 defined as security updates. Updates came yesterday afternoon.
Today I find on the bottom-right desktop "Activate Windows".
I re-entered my product key (as I did when I installed windows 7 ultimate and when I upgraded to windows 10 pro) and it was activated for more than two years (according to control panel --> system or settings --> update & security --> activation.
What happened?
What can I do?
(I didn't make any hardware changes except replacing my dvd writer with the same LG model)
Please help
thanks

restored to November 1 and the demand to activate on desktop disappeared but as soon as I'll get those updates. It will reappear.
I'm now in winver version 1803 build 17134.
I looked again in settings --> update & security --> activation and I saw the bizarre title on 2nd row across activation: unable to reach windows activation servers
is that why the sudden activation demand reappears? what does it mean? what can I do about it?
thanks

If you read posts on the forum it's happening to a lot of people and it's a MS fault you could update to 1809 see if it clears it but MS will solve it soon

thank you so much
If I only knew how to upgrade to 1809,,,,

Try to follow this post:
Issues Activating Windows 10 Solved - Windows 10 Forums

slmgr /ato

Working fine here in Oregon just now.

To update go here and hit update it will come via updates in time Download Windows 10

I still have "unable to reach windows activation servers" in settings --> update & security --> activation
so I'll wait a few days
but is it adviced to receive windows updates until the problem is solved here?
thank you

I would very highly recommend trying
slmgr /ato

Also, updating Windowed while not activated is no issue at all.

indeed after upgrading top 1809 the problem was solved
thanks a million, muchomurka!