I realize that by now this is getting tiresome, BUT.... I just created a fresh, two-column document in Office 365. I inserted a footnote in the LH column and then, because the experimental text runs over to the RH column, I inserted a footnote there. Footnote 1 appears at the foot of the LH column and f.n. 2 appears at the bottom of the RH column.
This whole issue appears to be nothing more than a glitch peculiar to the document I was originally editing. I do appreciate everyone's willingness to offer assistance. Thank you very much.