When header/footer (HeaderFooterPresenterBase) is rendered, the model which corresponds to it (HeaderFooterBase's Body property) is not updated. The result is updated only in the presenter. Thus, when exporting the document or when checking the elements in the model, the value of the inline (span's text) is not updated.

Workaround: Update the fields in the headers/footers. RadDocumentEditor.UpdateAllFields() method can be used. Note that it works only for the main document and not its child documents, so different RadDocumentEditors should be created for each header/footer document.