Hello, Firefox automatically creates backups of your bookmarks, which can be helpful if your bookmarks are lost or missing. Firefox must've somehow put them in reverse order when it was restoring them. For now, you can change them back by clicking and dragging them to the end to get them in correct order. We will look into this and create a patch for it. When you figure out what's causing your issues, please let us know. It might help others with the same problem.