Italics not showing in popup footnotes

I'm working on a new version of one of my ebooks at the moment, and thought it would be nice to have popup footnotes working on the Voyage. I've got the footnotes to appear in the popup window, but italics within the footnote are being displayed as normal text. If I select the "Jump to Footnotes" link at the bottom of the popup window to display the footnote full-screen, the italics appear correctly.

Is this the normal behaviour, or am I doing something wrong?

Thanks!