Ok, this always happens to me, too.  I am not 
100% sure, but what I _think_ is happening is 
that the mail is sent to a US facility in Japan, 
and then sent from that facility in Japan to the 
US.  So it is technically leaving US territory?

That's the best I've been able to guess...though 
there may be a better explanation.  Everything is 
fine with your package, though.  In another day 
or two, it will say that it has arrived in the US.

Rosemary