I have seen your issue once or twice over the years and second your question.

In the meantime, a potential workaround might be to create a fresh TOC. I have found it better to create the TOC using the References, Table of Contents, Custom Table of Contents option, rather than Word's autogenerated one, which places the TOC within a clunky content field. (I believe this is what I did, but you were smarter to post to the forums--hope someone has a solution for you, and good luck!)