Internal links broken when PDF'ing from Word

This issue began for me and several team members recently. (It then resolved itself and now is not working again.) We are using Adobe Acrobat Pro DC through Creative Cloud Online and Microsoft 365. 

The issue: When creating a PDF from a Microsoft Word document, hyperlinks created in Word should be retained in the PDF'd copy. However, for us, the external links (to webpages) are retained, but the internal links (to places within the document and the Table of Contents links) are not.

The way we create PDFs is by using the Acrobat toolbar in MS Word. In the Preferences settings, "Add Links" is checked. To launch the process, we select "Create PDF" which generates the PDF.

I have tested the same file outside our work environment - on my personal computer (I also have Adobe Acrobat Pro DC through Creative Cloud online), and all the hyperlinks are retained (both internal and external). So the problem is not the Word file itself. It seems to be environmental.

Could this be a problem with the Acrobat toolbar add-in, or maybe a security problem? Any ideas are welcome. Thanks in advance.

(We often have multi-hundred documents and manually linking within the Acrobat PDF file is really not a viable option.)