Occasionally, there have been instances where duplicate content appears when using the Feed to Post feature. This most likely is due to caching.
Caching plugins, and sometimes host server caching, do not have a way to detect and flush the cache for updated dynamic content. Therefore, content on the site, such as an RSS feed, won’t update properly when your site is being cached.
It is necessary to clear the cache files to avoid duplicate feed items or for feed items to update on the front end of your site.
If your theme or caching plugin is not clearing the cache automatically, we recommend contacting the plugin developer and asking if the plugin is compatible with dynamic content.