Entire WordPress Loading In Categories On Add Post Admin Page

This is really weird. Have never encountered this before. When I go to add a post, I see a loading dialog in the section where I select category. I also see my user name and log out link.

After a second, I see the wordpress admin panel there. Then, the entire page redirects to a page that just shows the top of the HTML text box for Add New Post.

I am stumped on why this is happening all of a sudden.