Problem occurs when saving a file created with WD2013 to WD2003WML
What happens: a rich text content control linked to a custom xml containing a content definition written as an xml part is not converted to WD2003WML but presented as a container containong OXML.
I have appended the WD2013 file and the result file.
I have tested the scenario and have managed to reproduce the same issue at my side. For the sake of correction, I have logged this problem in our issue tracking system as WORDSNET-9716. I have linked this forum thread to the same issue and you will be notified via this forum thread once this issue is resolved.