Make sure that the problem document is the active document in Word. Open the Templates and Add-Ins dialog box and clear the "Automatically update document styles" option. (To display the dialog box, first enable the Developer tab via File tab | Options | Customize Ribbon, and then click the Document Template button on the Developer tab.)
Set up numbering carefully linked to paragraph styles as discussed in the article at
http://shaunakelly.com/word/numberin...g20072010.html.