I'd contact the issuing AA, and ask about the release of bond, if the vehicle does not return home. Sent my bike home by sea in -08, and at least here the AA flat out refused to do anything with the bond, until I had the stamps from Finnish customs on the last page (certificate of location), that proved the vehicle had returned to Finland. Even though I had proper exit stamps from all carnet countries, that it had entered.
Dunno if this was just BS, that only happens here, or if it is a more common practice. I was surprised about that.