First, use the method shown at How to create numbered headings or outline numbering in Ribbon Versions of Word by Shauna Kelly to set up your numbering.


The way I would do this would not be with a cross-referenece to a bookmark but rather using a mapped rich-text Content Control. Duplicate the control.
Note, changes made in either location will show up in the other.


I have not tested your problem on my system yet nor have I tried my suggestion. I will do both later today, I suspect.