Originally Posted by Guessed

There are two different separators. The longer one is looks like it is a 'Footnote Continuation Separator' rather than a 'Footnote Separator'. I'm not sure what triggers the Continuation Separator and perhaps someone will chip in or you could do a Google search to figure it out. I would have assumed that the continuation separator appeared when a footnote was so large that it split across a second page but that doesn't appear to be the case with your short one line examples.

So I would just edit the separators so they are both the same appearance. To do this, change the view to Draft View and then double click on one of the footnote references. This will split the screen so you can see the footnote area at the bottom of the screen. There is a Footnotes dropdown that lets you select the Footnote Separator and the Footnote Continuation Separator. If you copy/paste from one to the other you should be able to give both the same appearance.