Actually it would be quite interesting to read about how the Web Archive accomplishes things like this.. Do they regularly scan news sites for new articles?
There is a self-archive tool on archive.org that allows anyone to immediately archive a specific page of interest. Journalists and watchdogs use it on pages they feel might disappear. It can be considered more legitimate that a screen capture, as archive.org is a third-party.
Someone might have used that here.
You can also request that the Web Archive fetch a URL from their homepage: https://archive.org/web/ ("Save Page Now" in the bottom right). I triggered the 7:09 copy this way; whether or not the other four fetches yesterday were also manual, I don't know.
I know if there's a controversial post that gets a lot of visibility, the IA staff takes a snapshot. They're useful in times like this where content is edited or deleted.
