When reporting the EU sales list to the Danish authorities, the VAT number comes from the customer and the country code should also come from the customer (invoice address).
If a sales order is delivered to Poland and invoiced to Sweden (Swedish customer), the EU sales list pick up the country code from the delivery address = PL, and that is wrong.
According to the rules in Denmark, country and VAT number should come from the customer (invoice address), even if the delivery is a part of triangular trade, where you deliver to one country and invoice to another country.