Since upgrading to the latest version of WordPress, a bunch of features are no longer working only when I am editing existing posts.
Specifically, the "Add Media" button, "Screen Options" at the top right, and a few plugins, including the Yoast SEO plugin.
If I add a new post, then everything works during that first session. But once I save a post and go back into it...poof...all this stuff breaks. Any ideas?