The Document Map in some versions of Word has a bad habit of including paragraphs that look like headings. To exclude such paragraphs from the TOC, do the following: Press Alt+F9 to show field codes instead of field results. The TOC looks similar to { TOC \o "1-3" \u \z \h }. Delete the "\u" part, and press F9 to update the TOC. Press Alt+F9 again to show the field result.

The reason you don't always get a dialog box when telling Word to update a TOC is that Word decides that it must update the whole TOC. This happens if headings have been added or removed from the document.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional