In the first image an undesired rule appears at the end of the column. The bottom footnote is finely placed to the left although this behaviour in other situations changes as in image 2
In the second image, when the following text goes to next page the situation is different. No rule. Although the footnote is placed to the right, that is not good at all. Conclusion? a footnote at the END of a splitted column behaves in different manners depending in something not exactly associated as it is the following text!
In the third image just a maremagnum is present. Footnote numbering is erroneous. Also position.
Finally, sometimes the footnote numbering fails and it has to be manually redone: when the footnotes definition is set to restart numbering every page, ID begins footnote numering in a new page page with number 2 instead of 1.