Error in OpenNI2 Code

I randomly get this ConcurrentModificationException on my console output on occasion.
The sensors seem to still get data, so not sure if it is harmful. I am unregistering my frame listener from within the frame listene itself, but not sure that would cause this problem.

Exception in thread "Thread-2503" java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextNode(
	at java.util.HashMap$
	at java.util.HashMap$
	at org.openni.VideoStream.onFrameReady(

Is the OpenNI2 2.3 source from Orbbec publicly available?