What permissions does a role need for the user to be assigned as the author of a post?
You probably need to add 3 capabilities: edit_published_posts publish_posts delete_published_posts but at the very least, you need to add publish_posts as that is the capability WordPress uses to determine what users are shown in Authors drop-down. Note: Changing capabilities is stored in the database so the recommendation is to modify these values via a plugin … Read more