No clue if it is related, but looking at the state diagram of MediaRecorder (
https://developer.android.com/reference/android/media/MediaRecorder), there are many situations in which reset() seems to be called that reverts the object back to a pre-setAudioSource state (looks like that method part of the Initialize method of AudioStreamer class). Please note that AudioStreamer is a combo of MediaRecorder and AudioTrack.