Teiid 8.9.1 throw null exception when use AVG function on jboss-eap 6.3

13:21:26,858 ERROR [org.teiid.PROCESSOR] (Worker0_QueryProcessorQueue20) N8zPomvnqZWy TEIID30019 Unexpected exception for request N8zPomvnqZWy.8: java.lang.NullPointerException
at java.util.ArrayList.addAll(ArrayList.java:559) [rt.jar:1.7.0_71]
at org.teiid.query.function.aggregate.Avg.getStateTypes(Avg.java:104) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.query.processor.relational.GroupingNode.collectionPhase(GroupingNode.java:415) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.query.processor.relational.GroupingNode.nextBatchDirect(GroupingNode.java:337) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.query.processor.relational.RelationalNode.nextBatch(RelationalNode.java:278) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.query.processor.relational.LimitNode.nextBatchDirect(LimitNode.java:102) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.query.processor.relational.RelationalNode.nextBatch(RelationalNode.java:278) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.query.processor.relational.ProjectNode.nextBatchDirect(ProjectNode.java:146) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.query.processor.relational.RelationalNode.nextBatch(RelationalNode.java:278) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.query.processor.relational.RelationalPlan.nextBatch(RelationalPlan.java:136) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.query.processor.QueryProcessor.nextBatchDirect(QueryProcessor.java:151) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.query.processor.QueryProcessor.nextBatch(QueryProcessor.java:114) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.query.processor.BatchCollector.collectTuples(BatchCollector.java:164) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.query.processor.BatchCollector.collectTuples(BatchCollector.java:146) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.dqp.internal.process.RequestWorkItem.processMore(RequestWorkItem.java:449) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.dqp.internal.process.RequestWorkItem.process(RequestWorkItem.java:331) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.dqp.internal.process.AbstractWorkItem.run(AbstractWorkItem.java:51) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.dqp.internal.process.RequestWorkItem.run(RequestWorkItem.java:259) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.dqp.internal.process.DQPWorkContext.runInContext(DQPWorkContext.java:274) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.dqp.internal.process.ThreadReuseExecutor$RunnableWrapper.run(ThreadReuseExecutor.java:119) [teiid-engine-8.9.1.jar:8.9.1]
at org.teiid.dqp.internal.process.ThreadReuseExecutor$3.run(ThreadReuseExecutor.java:210) [teiid-engine-8.9.1.jar:8.9.1]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [rt.jar:1.7.0_71]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [rt.jar:1.7.0_71]
at java.lang.Thread.run(Thread.java:745) [rt.jar:1.7.0_71]

teiid installer: teiid-8.9.1-jboss-dist.zip
jboss installer: jboss-eap-6.3.0.zip

original mysql data:

DROP TABLE IF EXISTS `time_function_test`;
CREATE TABLE `time_function_test` (
`id` int(11) NOT NULL,
`start_time` timestamp NULL DEFAULT NULL,
`end_time` timestamp NULL DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

LOCK TABLES `time_function_test` WRITE;
INSERT INTO `time_function_test` VALUES (1,'2007-12-31 16:00:01','2009-12-31 16:00:01'),(2,NULL,NULL);
UNLOCK TABLES;

vdb definition:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<vdb name="test" version="1">

<description>raw db data</description>

<model name="TeiidTest">
<property name="importer.useFullSchemaName" value="false"/>
<property name="importer.tableTypes" value="TABLE,VIEW"/>
<source name="test" translator-name="mysql5" connection-jndi-name="java:jboss/datasources/teiid-test-DS"/>
</model>

<data-role name="ReadOnly" allow-create-temporary-tables="true">
<description>Allow ReadOnly access to all data for any teiid-admins user</description>

<permission>
<resource-name>TeiidTest</resource-name>
<allow-create>false</allow-create>
<allow-read>true</allow-read>
<allow-update>false</allow-update>
</permission>

<mapped-role-name>teiid-role</mapped-role-name>
</data-role>
</vdb>

teiid query:
SELECT
AVG(TIMESTAMPDIFF(SQL_TSI_SECOND, tf.start_time, tf.end_time))
FROM
time_function_test tf
GROUP BY id