Проблема с аудифокусом в приложении (AudioManager.AUDIOFOCUS_GAIN)

Ситуация заключается в том, что в приложении исправно работает только один режим, при котором если поступает звонок, музыка прекращает играть. При завершении звонка, музыка продолжается.

Пользователи жалуются на то, что если поставить музыку на паузу, и далее (например) оповещение какое то придет на устройство, то музыка самопроизвольно начинает играть дальше. Как это возможно исправить? Код сервиса выкладываю ниже:

public class PlaybackService extends Service implements AudioManager.OnAudioFocusChangeListener {
private static final String TAG = Log.buildTag(PlaybackService.class);
public static final String ACTION_TOGGLE_PLAYBACK = "com.pro.actions.TOGGLE_PLAYBACK";
public static final String ACTION_STOP_PLAYBACK = "com.pro.actions.STOP_PLAYBACK";
public static final String ACTION_PAUSE_PLAYBACK = "com.pro.actions.PAUSE_PLAYBACK";
private static final int NOTIFICATION_ID = 1231231;
private final IBinder binder = new LocalBinder();
private PowerManager.WakeLock wakeLock;
private WifiManager.WifiLock wifiLock;
private RemoteControlClient remoteControlClient;
private ComponentName remoteControlReceiver;
private MediaSession mediaSession;
@Override
public void onCreate() {
    super.onCreate();
    EventBus.getInstance().register(this);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        mediaSession = new MediaSession(this, "com.pro");
        mediaSession.setFlags(MediaSession.FLAG_HANDLES_MEDIA_BUTTONS | MediaSession.FLAG_HANDLES_TRANSPORT_CONTROLS);
        final Intent intent = new Intent(this, MainActivity.class);
        mediaSession.setSessionActivity(PendingIntent.getActivity(this, 0, intent, 0));
    } else {
        remoteControlReceiver = new ComponentName(getPackageName(), PlaybackReceiver.class.getName());
        final Intent mediaButtonIntent = new Intent(Intent.ACTION_MEDIA_BUTTON);
        mediaButtonIntent.setComponent(remoteControlReceiver);
        final PendingIntent mediaPendingIntent = PendingIntent.getBroadcast(getApplicationContext(), 0, mediaButtonIntent, 0);
        remoteControlClient = new RemoteControlClient(mediaPendingIntent);
    }
}
@Override
public void onDestroy() {
    super.onDestroy();
    EventBus.getInstance().unregister(this);
    Streamer.getInstance().destroy();
    ensureUnlocked();
    releaseAudioFocus();
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        mediaSession.release();
    }
}
@Override
public int onStartCommand(final Intent intent, final int flags, final int startId) {
    final String action = intent != null ? intent.getAction() : null;
    if (ACTION_TOGGLE_PLAYBACK.equals(action)) {
        togglePlayback();
    } else if (ACTION_STOP_PLAYBACK.equals(action)) {
        stopPlayback();
        stopSelf();
    } else if (ACTION_PAUSE_PLAYBACK.equals(action)) {
        setPlaying(false);
    } else {
        return super.onStartCommand(intent, flags, startId);
    }
    return START_STICKY;
}
@Nullable
@Override
public IBinder onBind(final Intent intent) {
    return binder;
}
private boolean requestAudioFocus() {
    final AudioManager audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
    final int result = audioManager.requestAudioFocus(this, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN);
    return result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED;
}
private boolean releaseAudioFocus() {
    final AudioManager audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
    final int result = audioManager.abandonAudioFocus(this);
    return result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED;
}
private void ensureLocked() {
    if (wakeLock == null) {
        PowerManager powerManager = (PowerManager) getSystemService(POWER_SERVICE);
        wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "com.pro");
        wakeLock.acquire();
    }
    if (wifiLock == null) {
        wifiLock = ((WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE)).createWifiLock(WifiManager.WIFI_MODE_FULL_HIGH_PERF, "com.pro");
        wifiLock.acquire();
    }
}
private void ensureUnlocked() {
    if (wakeLock != null) {
        wakeLock.release();
        wakeLock = null;
    }
    if (wifiLock != null) {
        wifiLock.release();
        wifiLock = null;
    }
}
private void buildNotification(final Bitmap bitmap) {
    final NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    final Notification notification = PlaybackNotification.getInstance(this, bitmap, mediaSession);
    nm.notify(NOTIFICATION_ID, notification);
    startForeground(NOTIFICATION_ID, notification);
}
private void updateNotification() {
    final NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    final Streamer streamer = Streamer.getInstance();
    if (streamer.isStopped()) {
        nm.cancel(NOTIFICATION_ID);
        stopForeground(true);
    } else {
        Picasso.with(this).load(streamer.getStation().getIconUrl()).into(new Target() {
            @Override
            public void onBitmapLoaded(final Bitmap bitmap, final com.squareup.picasso.Picasso.LoadedFrom from) {
                buildNotification(bitmap);
            }
            @Override
            public void onBitmapFailed(final Drawable errorDrawable) {
                buildNotification(null);
            }
            @Override
            public void onPrepareLoad(final Drawable placeHolderDrawable) {
                buildNotification(null);
            }
        });
    }
}
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
private void startMediaSession() {
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP)
        return;
    mediaSession.setActive(true);
}
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
private void stopMediaSession() {
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP)
        return;
    mediaSession.setActive(false);
}
// FIXME support new api
private void registerRemote() {
    final AudioManager am = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
    if (remoteControlReceiver != null) {
        am.registerMediaButtonEventReceiver(remoteControlReceiver);
    }
    if (remoteControlClient != null) {
        am.registerRemoteControlClient(remoteControlClient);
    }
}
private void unregisterRemote() {
    final AudioManager am = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
    if (remoteControlReceiver != null) {
        am.unregisterMediaButtonEventReceiver(remoteControlReceiver);
    }
    if (remoteControlClient != null) {
        am.unregisterRemoteControlClient(remoteControlClient);
    }
}
private void duck() {
    Streamer.getInstance().setVolume(.25f);
}
private void unduck() {
    Streamer.getInstance().setVolume(1);
}
public void loadStation(final Station station) {
    Streamer.getInstance().loadStation(station);
}
public void togglePlayback() {
    final Streamer streamer = Streamer.getInstance();
    setPlaying(!streamer.isPlaying());
}
public void setPlaying(final boolean state) {
    final Streamer streamer = Streamer.getInstance();
    if (!state) {
        streamer.pause();
    } else {
        if (streamer.isStopped())
            streamer.loadStation(streamer.getStation());
        streamer.start();
    }
}
public void stopPlayback() {
    final Streamer streamer = Streamer.getInstance();
    streamer.stop();
    releaseAudioFocus();
    try {
        stopService(playIntent);
        int pid = android.os.Process.myPid();
        android.os.Process.killProcess(pid);
        System.exit(0);
    } catch (Exception e) {
        e.printStackTrace();
    }
}
@Override
public void onAudioFocusChange(final int focusChange) {
    switch (focusChange) {
        case AudioManager.AUDIOFOCUS_GAIN:
        case AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE:
        case AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK:
            setPlaying(true);
            unduck();
            break;
        case AudioManager.AUDIOFOCUS_LOSS:
            //stopPlayback();
            setPlaying(false);
            break;
        case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
            setPlaying(false);
            break;
        case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
            duck();
            break;
        default:
            break;
    }
}
@Subscribe
public void onMetadataUpdated(final StreamMetaDataUpdate update) {
    updateNotification();
}
@Subscribe
public void onPlayerStateChanged(final PlayerStateChange update) {
    updateNotification();
    if (!Streamer.getInstance().isStopped()) {
        ensureLocked();
        requestAudioFocus();
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            startMediaSession();
        } else {
            registerRemote();
        }
    } else {
        ensureUnlocked();
        releaseAudioFocus();
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            stopMediaSession();
        } else {
            unregisterRemote();
        }
    }
}
@Subscribe
public void onError(final PlayerError error) {
    updateNotification();
}
@Subscribe
public void onStationUpdate(final StationUpdate update) {
    updateNotification();
}
public class LocalBinder extends Binder {
    public PlaybackService getService() {
        return PlaybackService.this;
    }
} }