FireUntilHalt with persistence does not allow the process to continue and throws exception.

I am not sure it is a bug. I have simple flow like this:
Start->Ruleflow->...
And I am running it with persistence. I am running the process in this way:
ProcessInstance process = session.createProcessInstance(
"pid", parameters);
session.insert(process);
long processInstanceId = process.getId();
new Thread(new Runnable() {
public void run()

{ session.fireUntilHalt(); }

}).start();
session.startProcessInstance(processInstanceId);
And it breaks after executing the activation (I can see that the right side of the rule is run, as I put a variable in the process and it is there after the execution):
Exception in thread "Thread-6" org.drools.RuntimeDroolsException: Unexpected exception executing action org.drools.common.RuleFlowGroupImpl$DeactivateCallback@645ccb
at org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:996)
at org.drools.common.DefaultAgenda.fireUntilHalt(DefaultAgenda.java:1036)
at org.drools.common.AbstractWorkingMemory.fireUntilHalt(AbstractWorkingMemory.java:777)
at org.drools.common.AbstractWorkingMemory.fireUntilHalt(AbstractWorkingMemory.java:753)
at org.drools.command.runtime.rule.FireUntilHaltCommand$1.run(FireUntilHaltCommand.java:50)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
at bitronix.tm.resource.jdbc.JdbcConnectionHandle.prepareStatement(JdbcConnectionHandle.java:259)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at bitronix.tm.resource.jdbc.BaseProxyHandlerClass.invoke(BaseProxyHandlerClass.java:63)
at $Proxy20.prepareStatement(Unknown Source)
at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:505)
at org.hibernate.jdbc.AbstractBatcher.getPreparedStatement(AbstractBatcher.java:423)
at org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:139)
at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1547)
at org.hibernate.loader.Loader.doQuery(Loader.java:673)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:236)
at org.hibernate.loader.Loader.doList(Loader.java:2213)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2104)
at org.hibernate.loader.Loader.list(Loader.java:2099)
at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:378)
at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:338)
at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:172)
at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1121)
at org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)
at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:65)
at org.jbpm.persistence.JpaProcessPersistenceContext.getProcessInstancesWaitingForEvent(JpaProcessPersistenceContext.java:39)
at org.jbpm.persistence.processinstance.JPASignalManager.getProcessInstancesForEvent(JPASignalManager.java:40)
at org.jbpm.persistence.processinstance.JPASignalManager.signalEvent(JPASignalManager.java:23)
at org.jbpm.process.instance.ProcessRuntimeImpl$3.afterRuleFlowGroupDeactivated(ProcessRuntimeImpl.java:335)
at org.drools.event.AgendaEventSupport.fireAfterRuleFlowGroupDeactivated(AgendaEventSupport.java:168)
at org.drools.common.RuleFlowGroupImpl.setActive(RuleFlowGroupImpl.java:148)
at org.drools.common.RuleFlowGroupImpl$DeactivateCallback.execute(RuleFlowGroupImpl.java:301)
at org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:994)
... 5 more

If I run it with fireAllRules() after starting the process, it works fine, so I think it may be related with the new thead that the reactive mode uses. Do I may have some problems with my session persistence configuration?

Attached a test.