Word doesn't treat cross-references like equations in Excel: the program won't update them in real time, causing references that move to display incorrectly.To update all the references in a file, select the whole document and use the Update Field option.If you add or remove content that causes the referenced item to move, you can update the cross-reference.

(If it works in other versions, all the better; I originally had this problem with Word 2007, and nothing seems to have changed since then.) This includes cross-references, page numbers, tables of contents, indexes, headers, etc.
If it can be updated by pressing , I want it updated.
On the other hand, if you don't want to update other items, you need to select your cross-references more carefully.
Instead of selecting the entire document, select individual cross-references or a few paragraphs at a time to make sure you don't include items you want left alone.
(In theory updating fields can cause other fields to need updating, e.g.