Hi, this seems to be a glitch that occurs when FB is more zoomed in or has less vertical space: the calculation of when Firefox needs to scroll goes a bit haywire. This has been found in versions as far back as Firefox 78, so it seems to be related with a change made by Facebook that isn't fully compatible with Firefox. The problem is on file with the developers, and people are looking at it, but I don't expect a fix for at least another month.

Until then, you might need to use a different browser for Facebook, or try to fit more content (vertically) into the window. For example, try F11 full screen to temporarily hide the toolbar, or zoom out (hold down the Ctrl key and tap the - key). With F11 full screen, the toolbar roll down when you move the mouse pointer to the top of the screen, or tap F11 again to return to normal view.

There have been numerous reports here and three bug reports. The more specific remaining one is https://bugzilla.mozilla.org/show_bug.cgi?id=1781145

The problem is, when Firefox does an update, something screws up, and the next update never fixes it. No other browser does these useless updates.

You just did an Update, and NEVER fixed the issue, NO other browser does this crap 8-31-22

This might happen if you are scrolling the page faster than the posts are loading, when the posts are being loaded, the page jumps. So you can try to scroll slower, especially if you notice that extra content is being loaded.

There is a bug on file for this and it is being studied to understand why it happens.

I know this is an ongoing issue, today was the third update and they never fixed it. If this was my car, they would be in court for damages.

After 4 updates now, this still isn't fixed, Firefox is useless.