fixed widgets shows a wrong content

I use a plugin named ‘fixed widgets’ to show contents of posts on right sidebar. It uses ‘Githuber TOC : MD’ to show contents. I have given a link of an example page. However, the contents on the right shows wrong. It always included the title of related posts and treat the title as the last part of contents. Could you please help me fix it?

The page I need help with: [log in to see the link]