AsyncEventListener behavior

I understand that if I set up a redundant AsyncEventListener to process region events the queue will fail over to the redundant queue during a node failure with a possibility that some events may be duplicated (hence the AsyncEvent.getPossibleDuplicate() method). My question is is there a possibility that duplicate events will happen during a normal node shutdown where the redundant queue becomes the primary queue? Or does this happen only when there is a crashed member? In other words will the AsyncEventListener wait until the processEvents(List<AsyncEvent> events) method has finished before it terminates or not?