TinyMCE Editor in Internet Explorer "moves" <fn> tags

By default the TinyMCE editor is enabled. I'm using the footnote module in conjunction with the editor. I have placed a footnote in the content as follows:

Here is an example of a footnote <fn>Insert footnote text here</fn>

I inserted the code directly into the source HTML and it works fine after I update the TinyMCE display and Submit the content. The footnote appears properly.

BUT

When I edit the document, the TinyMCE editor appears by default and when I go into the source the TinyMCE editor has messed up the footne tags and they now look like this:

Here is an example of a footnote <fn></fn>Insert footnote text here

In other words, the text that was in the footnote has not been lost but the footnote closing tag has been moved by the TinyMCE editor.

1. This only occurs in IE (I only have IE 7). Formatting is not messed up in Firefox.
2. If I change my user preferences to disable the Rich Text Editor, the fn tags are in their proper place. If I then enable and then disable the editor, the fn tags get shifted over.