The file exported to docx cannot be reimported by preceding version of the richtextbox.
The workaround doesn't work for us. When using RadFlowDocument, the current implementation of the DocxFormatProvider
does not include support for exporting change tracking information (e.g., tracked revisions, insertions, deletions). This means that when you save a document with tracked changes using this provider, the changes will be "finalized" or "accepted" within the DOCX file, and the tracking information will not be preserved.