Your periodic reminder that just because a URL is saved at archive.org doesn't mean it's going to stay there.
Last year, I wrote a series about proxy services marketed to cybercriminals, and that relied heavily on Archive.org links to document various connections. After my story ran, the person that those links concerned asked Archive to remove those links from their database, which they did. The person in question came back and said hey, what you said in your story is wrong because there's no supporting evidence and you must remove this. Archive.org confirmed they removed all of the pages at the request of the domain holder, and that was that.
If you stumble upon a page that is in archive.org and you want to make sure there is a record that won't be deleted at some point, consider saving the page to archive.today/archive.ph
Alternatively, of course, you could save the page locally, using something like Firefox's built-in full page screenshot (right click on page). Better yet, save the Archive.org pages you want locally.