I had an issue with a Word 2010 document whose table of contents entries were ridiculously off–entries being on page 45 of a 24-page document, for example.

The problem appeared to be due to track changes. The pages it was putting in the table of contents seemed to correspond with the page numbers of the marked-up document. Unfortunately, the only way I found to fix the issue was to accept all the changes in the document, but after I did that, the table of contents updated correctly.