While in Walmart a few days ago I was looking over the DEF containers. None of the 1 gallon and 2-1/2 gallon jugs had a production date stamped on the jug like they once did. They do still have the API certification on the label but didn't see ISO 22241. I have used Supertech DEF exclusively since I bought the truck with "0" issues, now without the production date I am having second thoughts. Anyone have any thoughts on this.