Very odd indeed. May have just been a caching issue with the CSS file where the old version from a previous version of JFBConnect was being loaded incorrectly. Either way, the important thing is that it works. Of course, if you run into any other issues, just let us know.
Finally, if you haven't already, please consider leaving a rating and review for JFBConnect, or our support, on the Joomla Extension Directory. It certainly isn't required, but is very appreciated:
extensions.joomla.org/extensions/social-...ook-integration/7215
Thanks,
Alex