Hi Susan

The best solution is to use the 'page break before' paragraph setting on the
heading, instead of inserting a manual break.

This is a manifestation of a general problem with bookmarks (your
cross-reference heading has a hidden bookmark inserted by Word). If you have
your cursor at the beginning, anything you type or insert will be caught
into the bookmark. Conversely, if you have your cursor at the end, anything
you type will fall out of it (annoying if you extend your heading title). To
stay safe, get into the habit of going to the last paragraph of the section
before, pressing return, adding anything you wish to add, and then delete
the excess paragraph end if you need to.

This 'feature' does interfere with using Outline view once X-refs have been
entered, too - getting 50 pages you moved in the Outline showing in your
cross reference is no joke ;-)