Free instance of agreggate with cas multiplier in MultiprocessingAnalysisEngine

I have a aggregate analysis engine that contains 2 casmultiplier
annotators. I instantiate this aggregate with the interface
UIMAFramework.produceAnalysisEngine(specifier, 1, 0) for multithreaded
processing. The last casmultiplier generate more than one cas for each
input CAS from first casmultiplier. The issue is that after first time that the last casmultipler's hasNext method method returns false, the MultiprocessingAnalysisEngine_impl assumes that the instance of
AggregateAnalysisEngine that processes the request has ended, and
then this instance is free to process ahother request from other thread, and it is not true, because missing child cas to process from de first casmultipler, producing concurrency errors.