[iOS] After invoke PlayFullScreenMovie(), if get phone call and return my app, sound system not works!!!!!

I tested iPhone4 (iOS 6.0.1).
Our app has an intro movie (MP4).
I played it using PlayFullScreenMovie() method.
After invoke PlayFullScreenMovie, get the phone call and return app.
Sound does NOT play.

For test, I built my app ‘no mp4 version’. It works well.

Please answer ASAP !

This is a bug in iOS and should hopefully be patched in future iOS versions. We’ve seen this happen a few times and been in contact with Apple about it, but unfortunately there isn’t anything we can do on our end to fix the issue.