A family of Microsoft word processing software products for creating web, email, and print documents.
This kind of issues are usually caused by incorrect cross-references. These, in turn, may be the result of pressing Enter at the beginning of a cross-referenced paragraph, which expands the hidden bookmark to include the newly created paragraph. The workaround is to always create new paragraphs, or add content, at the end of a paragraph of text. For existing documents, recreating the cross-references will be the easiest solution.
To clarify, a hidden bookmark is created by Word each time you create a cross-reference via the Cross-reference dialog box (unless of course you are creating a reference to an existing bookmark).