CComment docs
Cache
CComment doesn't support Joomla'sProgressive caching, due to a bug in Joomla. Because of that bug Javascript gets added twice to the head of the HTML document and that is wrong (more info here). Currently we don't know of any workaround, that is why we advise you if you want to use cache on your Joomla site to useConservative cachingor to opt for more advanced options such as memcache or varnish.