Thank you for posting to our forum!
I took a look at your account and Shipment History and saw that the international label you are sending is a First Class Large Envelope/Flat. The process for those types of labels is a bit different than other labels. It goes to a processing facility before it is sent to the end-customer. You can see more about this here: How to: Select a Large Envelope/Flat to ship international
I hope that helps clarify things for you!