InfoPath Dev

I have a infopath form published to sharepoint and I've made several fields on the form available as sharepoint list columns.  If I make a change to the infopath form and republish it to sharepoint i lose all the data in these fields for all the previously submitted forms.  If I open each form and resubmit it the values will be populated again.  Is there a way to make a change to a form and republish it to sharepoint without losing the data in the sharepoint columns?   

 In the InfoPath form, are you promoting the properties (fields) you want to show in SharePoint?

Yes the fields have been promoted as columns in the sharepoint forms library.  One thing I didn't mention is that I have published the form to two different libraries in sharepoint.  I allow users to enter data on one then use a workflow to move the form from there to the second library that I published the form to where admins can manage the request made on the form.  This allows me to have different permissions on each library so users inputing requests can't access the list of requests that have been submitted.  Now, if I make a change to the form and republish it I lose the values in the sharepoint list columns that have been promoted.  If I open each form and save it the values will come back, but this is a problem when a lot of forms have been submitted and a change is needed.  Any ideas? 

Thanks for posting the additional info. If I were you I would try to publish a test form library, without workflow, to see if the properties are being promoted correctly by InfoPath. If they are (you detect no issues), then the problem definitely lies with the workflow. Then I would recommend you post this in the SharePoint integration forum. Unfortunately, once SharePoint workflow is involved it's a tad more difficult to figure out. Good luck.

I did as you suggested.  I published a form to sharepoint and selected a couple of fields to be used as columns in the sharepoint list.  I submitted a form then opened the form in infopath and made a simple change, republished the form to the same sharepoint list and again I lost the values in the columns that were promoted from the form.  This was with no workflow involved.  I can open the existing forms and save them again and the data in the columns will be populated. 

I have this exact same issue and so far have not found any solutions other than to manually open each and every form in the library, make no changes to the data within the form, and just close it.  That is VERY annoying when we have several hundred to even a thousand + forms submitted in the library already.