Can you re-order the System - JFBCSystem plugin so it has a lower number position? My guess is that you have some optimization or caching plugin running on your site that's executing before our plugin. You'll need to make sure any optimization/caching plugins are executed last so that all the other plugins, including ours, have done their work before the results are saved by the caching plugin.
I hope that helps, but if not, let us know.
Thanks,
Alex