With MongoDB, a query with subquery in HAVING clause doesn't return any results

SELECT INTKEY FROM BQT1.SMALLA GROUP BY INTKEY HAVING INTKEY = (SELECT INTKEY FROM BQT1.SMALLA WHERE INTKEY = 20) 

SELECT INTKEY FROM BQT1.SMALLA GROUP BY INTKEY HAVING INTKEY = 20;

SELECT INTKEY FROM BQT1.SMALLA GROUP BY INTKEY HAVING INTKEY = (SELECT null);

13:43:50,250 ERROR [org.teiid.CONNECTOR] (Worker1_QueryProcessorQueue1) Connector worker process failed for atomic-request=mo0zm9PiOEre.0.3.0: java.lang.NullPointerException
	at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:936) [rt.jar:1.8.0_151]
	at org.teiid.translator.mongodb.MongoDBSelectVisitor.getExpressionAlias(MongoDBSelectVisitor.java:808) [translator-mongodb-8.12.11.6_4-redhat-64-12.jar:8.12.11.6_4-redhat-64-12]
	at org.teiid.translator.mongodb.MongoDBSelectVisitor.visit(MongoDBSelectVisitor.java:641) [translator-mongodb-8.12.11.6_4-redhat-64-12.jar:8.12.11.6_4-redhat-64-12]
	at org.teiid.language.Comparison.acceptVisitor(Comparison.java:110) [teiid-api-8.12.11.6_4-redhat-64-12.jar:8.12.11.6_4-redhat-64-12]
	at org.teiid.language.visitor.AbstractLanguageVisitor.visitNode(AbstractLanguageVisitor.java:51) [teiid-api-8.12.11.6_4-redhat-64-12.jar:8.12.11.6_4-redhat-64-12]
	at org.teiid.translator.mongodb.MongoDBSelectVisitor.append(MongoDBSelectVisitor.java:81) [translator-mongodb-8.12.11.6_4-redhat-64-12.jar:8.12.11.6_4-redhat-64-12]
	at org.teiid.translator.mongodb.MongoDBSelectVisitor.visit(MongoDBSelectVisitor.java:574) [translator-mongodb-8.12.11.6_4-redhat-64-12.jar:8.12.11.6_4-redhat-64-12]
	at org.teiid.language.Select.acceptVisitor(Select.java:110) [teiid-api-8.12.11.6_4-redhat-64-12.jar:8.12.11.6_4-redhat-64-12]
	at org.teiid.language.visitor.AbstractLanguageVisitor.visitNode(AbstractLanguageVisitor.java:51) [teiid-api-8.12.11.6_4-redhat-64-12.jar:8.12.11.6_4-redhat-64-12]
	at org.teiid.translator.mongodb.MongoDBQueryExecution.execute(MongoDBQueryExecution.java:60) [translator-mongodb-8.12.11.6_4-redhat-64-12.jar:8.12.11.6_4-redhat-64-12]
	at org.teiid.dqp.internal.datamgr.ConnectorWorkItem.execute(ConnectorWorkItem.java:361)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [rt.jar:1.8.0_151]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) [rt.jar:1.8.0_151]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [rt.jar:1.8.0_151]
	at java.lang.reflect.Method.invoke(Method.java:498) [rt.jar:1.8.0_151]
	at org.teiid.dqp.internal.datamgr.ConnectorManager$1.invoke(ConnectorManager.java:211)
	at com.sun.proxy.$Proxy79.execute(Unknown Source)
	at org.teiid.dqp.internal.process.DataTierTupleSource.getResults(DataTierTupleSource.java:306)
	at org.teiid.dqp.internal.process.DataTierTupleSource$1.call(DataTierTupleSource.java:112)
	at org.teiid.dqp.internal.process.DataTierTupleSource$1.call(DataTierTupleSource.java:108)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [rt.jar:1.8.0_151]
	at org.teiid.dqp.internal.process.FutureWork.run(FutureWork.java:65)
	at org.teiid.dqp.internal.process.DQPWorkContext.runInContext(DQPWorkContext.java:284)
	at org.teiid.dqp.internal.process.ThreadReuseExecutor$RunnableWrapper.run(ThreadReuseExecutor.java:119)
	at org.teiid.dqp.internal.process.ThreadReuseExecutor$3.run(ThreadReuseExecutor.java:210)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [rt.jar:1.8.0_151]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [rt.jar:1.8.0_151]
	at java.lang.Thread.run(Thread.java:748) [rt.jar:1.8.0_151]

13:43:50,257 WARN  [org.teiid.PROCESSOR] (Worker0_QueryProcessorQueue2) TEIID30020 Processing exception for request mo0zm9PiOEre.0 'TEIID30504 local: null'. Originally TeiidProcessingException ConcurrentHashMap.java:936. Enable more detailed logging to see the entire stacktrace.