One of the User Role Editor plugin users asked me, why user loses edit posts capabilities assigned to him directly. The issue takes place on a regular basis.
You assign to the user ‘edit_posts’, ‘edit_published_posts’ capabilities with other post’s related capabilities together. But after login and opening ‘Posts’ menu item that user loses his access to the ‘Posts’ menu. If you check his user capabilities after that you will see that he lost all edit post capabilities somehow. Read more Why user loses edit post capabilities or IgnitionDeck Framework special feature