Steps to replicate:
- Open any page on Beta cluster with VE
- Go to Settings, and make sure the option "Disable the edit links next to each heading on this page." is checked
- Also, enable "Show a tab on this page to add a new section"
- Now click on new section tab and add a new section
- Click on "Publish Changes"
The section heading of the section that has been just added appears on top of the TOC momentarily.