You probably are using the System - Cache plugin, but it's not ordered last (the highest number). The System - Cache plugin should be last so that it's saving/caching the page after all the other system plugins (like JFBCSystem) have modified the page. Otherwise, it will be saving prematurely. So, try increasing the order of the System - Cache plugin and then clearing your Joomla cache.
Test that, and if you still have issues, let us know.
Thanks,
Alex