Yoast only looks at the_content – that is, the content in the main, default WP editor. If your other plugin stores the content of posts in any other way, Yoast won’t see that content. You’ll probably be best off just disabling content analysis in Yoast if you’d like to continue using that plugin. Or, you can look for a different way – other than the article plugin – to accomplish your publishing goals but still store the content in the main editor, thus allowing Yoast to analyze it.
