What did you use to create the document?
But, since this IS most likely for footnotes, I'd just stick to a simpler method (such as using "(4)"). I wouldn't necessarily
like having to do it that way, but fanfiction.net
DOES have a tendency to suddenly start disallowing special characters/arrangements at odd moments, and I know you'd hate to look at the posted chapters after two to three months and discover the changes have horribly broken them.
Not that there's a guarantee they still wouldn't break the stories, but...