Facebook recently announced their new search feature was coming, and it would seem the update may be coming around as the Top Bar on Facebook has completely disappeared. This is annoying as I can’t check the notifications or messages I might have until it has been restored.
This is what it currently looks like from the top of the webpage down for me. I am not sure if it is a worldwide thing, but updates usually get rolled out gradually so it may not be affecting too many people.
I have confirmed that other people have also been seeing the error and they can confirm that they indeed are, and there are some tweets related to it too: