Try this:

1. Create a new paragraph that's not part of the TOC.
2. Format it with the TOC4 style. Is the rogue tab stop present? If so, delete the tab stop and update the style.
3. Then regenerate the TOC. If the tab stop returns, then it's almost certainly the Jason tab referenced earlier, and you may just have to live with it--Every time you generate the TOC, delete the tab stop and update the style--that should correct all the affected TOC paragraphs.