The solution was eventually provided in this question:
Android (Samsung S4) HTML5 video pauses
Adding this:
pause();
((AudioManager)activity.getSystemService(
activity.AUDIO_SERVICE)).requestAudioFocus(
new OnAudioFocusChangeListener() {
@Override
public void onAudioFocusChange(int focusChange) {}
}, AudioManager.STREAM_MUSIC,
AudioManager.AUDIOFOCUS_GAIN_TRANSIENT);
to the SDK onPause method here:
fixed the problem.
I filed a defect to Appcelerator. Hope they include this soon in their SDK.