Good news! After I called my post office, the item reappeared in the US and was delivered today. I wonder if my phone call helped. I only called because my buyer complained. When my package from Hawaii got stalled for a week, it seemed to start moving right after my seller called the PO.
I learned another thing from the rep at my PO. When they scan a package at each point during the process, they take a picture of the package. That way, they can see that the package left the processing facility in the same condition as it went in, and when they go to deliver it, they know if it was damaged along the way and where that damage occurred. When they take these pictures, they can see the address label and know if it is intact. I'm always concerned that it will become illegible and undeliverable, so it is reassuring to find out that the label remained readable on its "world travels."