This plugin is adding a header to my RSS feeds. I isolated the problem to this plugin by turning all plugins off and enabling one by one.
When logged as an admin the RSS feed (http://sociedadastronomia.com/feed) includes the whole WordPress header (admin bar) at the top. When not logged in (using an Incognito window) it shows a "Generated in [x] seconds." html comment and an empty div tag.
Both breaks the feed since they are added before the XML header, preventing it from validating.
Any clue as to what may be causing this?
Again, I already checked the other plugins. Problems appear when enabling this one.