To start in safe mode with your document

1. Close Word.
2. Find the icon for the document giving you problems.
3. Hold down your Ctrl key.
4. Double-click on the icon for your document to open it with the Ctrl key down.
5. Release the Ctrl key
6. Word should ask you if you want to start in safe mode
7. Answer yes

What you are seeing does not mean that it is updating, it means that the Content Control around the TOC is there.

I generally avoid using either of the building blocks which add that Content Control. I use the Custom TOC which just inserts the field without the Content Control. The Content Control adds no value and slows things down.