I am having the same problem as well. I have changed nothing in my shipping settings and the cart has worked fine until now, it's always shown USPS First Class International and USPS Priority Global as the two options. Now it just picks USPS Global Priority rates by default and there is no drop down menu for other options (it also doesn't state anywhere for the customer to see, that the rate it's using is USPS Global Priority). I went into my shipping admin to see if anything has changed - nothing as far as I can see. Have received a couple complaints already today.
Thanks.
-Lily