Message event data gives empty data sporadically even we get the event ID correctly

[praveendroid]

While getting the Message event data on onMessage() call back if we push continuously for some time it gives empty messageEvent.data.
For example, if I receive message event data 10 times then 2 or 3 times it gives messageEvent.data as empty.
public void onMessage(String event, MessageEvent messageEvent) throws Exception {
Log.e(TAG, "onMessage : " + "SSE Message Event received : " + messageEvent.data);
}

here messageEvent.data is " " as i mentioned it happens 2 or 3 times out of 10