Hi Casey,
Thanks for your updates. My name is Josh Wells and I am a support engineer on the Microsoft Dynamics CRM support team.
So I have reviewed this situation and I am not quite sure where the issue is at. I created a Mail Merge Template and saw that the data was there within the data set:
Next, I was able to add it within my document:
Ensure you are adding the proper field for Product Description if that is truly what you are trying to get at.
Hope this helps you out.