Checkbox control from OOXML format getting converted into "?"

I am working on a Word Addin/Office JS Project which deals with Word templates. My requirement is to load the static table into template when the user clicks on the Addin.

Step 1: Converting Static Table Data into OOXML and Storing it into Database.

Sample Table Structure:Image1

This Table has Check box controls and Content Control inside it. I am generating OOXML for this loading it into database.

Code

var body = context.document.body;

var bodyOOXML = body.getOoxml();

Step 2: Retrieving the table data from Database and loading it in the document when the user click on the addin.

Code

 var body = context.document.body;

 body.insertOoxml(currentOOXML, Word.InsertLocation.replace);

but when I retrieving the table data, the check box control in the table are displayed as "?"

Please find the sample below

Sample Table Structure:

Can some one help me with this: I don’t understand why checkbox controls are getting converted as "?"

If I click on "?" its converting back into a Checkbox