TaxJar integration not respecting Product Tax Category

I am using ERPNext Version 14 and configured the TaxJar integration. When adding an item to a sales invoice, the first Item in the sales invoice has a product category, the second item has no product category. My expected outcome is that the first item would be taxed and the second item would not be taxed. However, just the opposite happens. Has anyone else had this issue?
Thanks,