Why would DJI void the warranty in Japan just because you took the drone to another country.
Just ask them how they're handling such cases. Worst case, you won't care for the answer, but they've not going to be vindictive because you asked.
You missed the point. It doesn't matter what the FAA does as long as the FCC does not certify new DJI drones.
But I updated my avatar, so I'll be protected.