Another technical question

Why am I suddenly getting this message when I click preview to review a post?

"Your submission could not be processed because a security token was missing.

If this occurred unexpectedly, please inform the administrator and describe the action you performed before you received this error."

I tried to preview a post to see if I would get the same message and didn't have any trouble with it. Does it only happen when you preview posts?

That's the only time I remember seeing it. It's happened several times last night and today. And it's random, not every time.

Scratch that! It didn't happen when I previewed this one; but it did when I clicked submit. I'm going to try it again. That usually works.

A new pop up has just appeared a few minutes ago (but not 1 hour ago). Is the mess starting all over again?!

It's a cookie consent message, just click Got It and it will not be displayed again. Only users in EU will see it, legal + Google's requirement.

Yeah, I know, I can read, TY!
My point was to underline the fact that there's a new popup after months of none, that's why I'm wondering whether it is the start of a new 1 million popups a day era...

It is clearly not an advert, so if you could refrain from scaremongering, that would be wonderful.