Hi Joel, it seems to be a blog post and not a Facebook page, but I definitely see the problem.

This is a classic case of a site using a style rule that makes Firefox treat a block of text as "unbreakable." Firefox moves the block to its own page and fills the page, but then the rest just runs off the bottom. Firefox doesn't "paginate" the block onto more pages because it treats it as unbreakable.

In this case, the main section of the page is set to display:flex, which Firefox won't paginate. It's a known problem that has been on the "to do" list for a while. You can work around it by tweaking the page with a script, but I know that's a hassle so I won't even go into the details unless you're interested.

Hi Joel, I started working on an add-on to make pages print better in Firefox. It's very rough at this point, but I wanted to mention it before I lose track of this thread.

https://addons.mozilla.org/firefox/addon/printable-the-print-doctor/