My working theory is that one (or more) of your authors is using the browser editing rather than opening the file with the Word application. I'm pretty sure the issues with lists are spawned by the browser editor.

I would recommend you configure Sharepoint to open the doc in the application to avoid the default browser view tempting your authors. And ask around to find out who edits via the browser or Word.

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Andrew Lockton
Chrysalis Design, Melbourne Australia