Email subject from Facebook: "Facebook Warning"

Hi - I got an email supposedly from Facebook that said the following: "Hello,
We have reviewed your request and made the appropriate changes. Sorry for any inconvenience. For more information about pages or other topics, please visit the Help Center: [You must be registered and logged in to see this link.] - The Facebook team"
I was dubious about the link, so didn't click, but typed in the URL directly, which took me to a Facebook 404 page. Then when I went back in to my news feed, this notice came up:
[You must be registered and logged in to see this image.]

I haven't clicked anything. Is this genuine? What should I do next?

The e-mail looks legit as you got a warning in your Homepage.

You didn't contact Facebook at all before this? Not even filled out a contact form? If not, check your recent logins to see if someone tried to access your account.

Account => Account Settings => Account Security => change => Your recognized devices.

The [You must be registered and logged in to see this link.] page doesn't seem to exist for me either. Has anything at all changed in your page? Maybe its username, or its category?

No, all seems to be standard. And I haven't contacted Facebook for some time, as I don't generally hear anything back ;-) Did report this issue though, just in case. I've changed my password, but the warning on the home page is still there. It looks like it will remain there until I click the 'Acknowledge' button, which I'm a bit hesitant to do...

I'd wait for Facebook's response before acknowledging anything.