Counter-intuitively, the behaviour your fourth member is experiencing may be due to the way their network and internet connections are set up, rather than being anything to do with Word, per se.

The simplest solution for all users might be to:
1. make a copy of the document;
2. delete all content from the copy;
3. uncheck the 'Automatically update document styles' option;
4. save the copy as a template using the same name and location as the original template. If the server name has changed, you'll need to update the template path to take account of that; and
5. ensure all users' systems have access to the network folder where template is located or, if it's saved locally, that they save a copy to the relevant local folder.

Aside from anything else, that should also make opening the documents somewhat faster than it is now. That's because, when a Word template is missing, Windows will try to locate the missing template multiple times. That process may cause a Word document to take longer than usual to open.

If a user is opening the file from a completely different location (e.g. at home instead of at work), simply disconnecting from the internet while opening the file can improve performance.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]