javax.persistence.OptimisticLockException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1 in BPM Suite with Singleton strategy

Issue

• I hit the following Exception when calling abortProcessInstance() even with one thread working.

11:18:55,943 WARN  [org.drools.persistence.SingleSessionCommandService] (default task-39) Could not commit session: javax.persistence.OptimisticLockException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.wrapStaleStateException(AbstractEntityManagerImpl.java:1729)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1634)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1602)
    at org.hibernate.jpa.internal.QueryImpl.getResultList(QueryImpl.java:492)
    at org.jbpm.persistence.JpaProcessPersistenceContext.getProcessInstancesWaitingForEvent(JpaProcessPersistenceContext.java:106)
    at org.jbpm.persistence.processinstance.JPASignalManager.signalEvent(JPASignalManager.java:46)
    at org.jbpm.workflow.instance.impl.WorkflowProcessInstanceImpl.setState(WorkflowProcessInstanceImpl.java:387)
    at org.jbpm.workflow.instance.impl.WorkflowProcessInstanceImpl.setState(WorkflowProcessInstanceImpl.java:394)
    at org.jbpm.process.instance.ProcessRuntimeImpl.abortProcessInstance(ProcessRuntimeImpl.java:474)
    at org.drools.core.impl.StatefulKnowledgeSessionImpl.abortProcessInstance(StatefulKnowledgeSessionImpl.java:551)
    at org.drools.core.command.runtime.process.AbortProcessInstanceCommand.execute(AbortProcessInstanceCommand.java:55)
    at org.drools.core.command.runtime.process.AbortProcessInstanceCommand.execute(AbortProcessInstanceCommand.java:30)
    at org.drools.core.command.impl.DefaultCommandService.execute(DefaultCommandService.java:36)
    at org.drools.core.command.impl.AbstractInterceptor.executeNext(AbstractInterceptor.java:41)
    at org.drools.persistence.SingleSessionCommandService$TransactionInterceptor.execute(SingleSessionCommandService.java:604)
    at org.drools.core.command.impl.AbstractInterceptor.executeNext(AbstractInterceptor.java:41)
    at org.drools.persistence.jpa.OptimisticLockRetryInterceptor.execute(OptimisticLockRetryInterceptor.java:82)
    at org.drools.core.command.impl.AbstractInterceptor.executeNext(AbstractInterceptor.java:41)
    at org.drools.persistence.jta.TransactionLockInterceptor.execute(TransactionLockInterceptor.java:73)
    at org.drools.persistence.SingleSessionCommandService.execute(SingleSessionCommandService.java:397)
    at org.drools.core.command.impl.CommandBasedStatefulKnowledgeSession.abortProcessInstance(CommandBasedStatefulKnowledgeSession.java:147)
    at org.jbpm.examples.service.ProcessBean.abortProcess(ProcessBean.java:54)
    ...
Caused by: org.hibernate.StaleStateException: Batch update returned unexpected row count from update [0]; actual row count: 0; expected: 1
    at org.hibernate.jdbc.Expectations$BasicExpectation.checkBatched(Expectations.java:67)
    at org.hibernate.jdbc.Expectations$BasicExpectation.verifyOutcome(Expectations.java:54)
    at org.hibernate.engine.jdbc.batch.internal.NonBatchingBatch.addToBatch(NonBatchingBatch.java:46)
    at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3134)
    at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:3013)
    at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3393)
    at org.hibernate.action.internal.EntityUpdateAction.execute(EntityUpdateAction.java:145)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:582)
    at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:456)
    at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:337)
    at org.hibernate.event.internal.DefaultAutoFlushEventListener.onAutoFlush(DefaultAutoFlushEventListener.java:50)
    at org.hibernate.internal.SessionImpl.autoFlushIfRequired(SessionImpl.java:1251)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1319)
    at org.hibernate.internal.QueryImpl.list(QueryImpl.java:87)
    at org.hibernate.jpa.internal.QueryImpl.list(QueryImpl.java:606)
    at org.hibernate.jpa.internal.QueryImpl.getResultList(QueryImpl.java:483)
    ... 71 more

• I hit the same Exception when I start a Task.