RS setting last usage in a group

RedScreen on chaise tomcat4 8.4.4
2013-08-26 11:43:58,707 [ajp-apr-8004-exec-63] ERROR DBRuntimeException - OLAT::ERROR ^% N4-E15 ^%
Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0) ^% *RedScreen* commit failed, rollback transaction :::: :::: ^%
>>> stack of 1.cause::org.olat.core.logging.DBRuntimeException: commit failed, rollback transaction
-> at org.olat.core.commons.persistence.DBImpl.commit(DBImpl.java:814)
at org.olat.group.manager.BusinessGroupServiceImpl.setLastUsageFor(BusinessGroupServiceImpl.java:327)
at org.olat.group.ui.run.BusinessGroupMainRunController.<init>(BusinessGroupMainRunController.java:235)
at org.olat.group.ui.BGControllerFactory.createRunControllerFor(BGControllerFactory.java:96)
at org.olat.group.BusinessGroupContextEntryControllerCreator.createController(BusinessGroupContextEntryControllerCreator.java:68)
at org.olat.NewControllerFactory.launch(NewControllerFactory.java:236)
at org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:202)
at org.olat.core.dispatcher.DispatcherAction.execute(DispatcherAction.java:154)
at org.olat.core.servlets.OLATServlet.doPost(OLATServlet.java:155)
at org.olat.core.servlets.OLATServlet.doGet(OLATServlet.java:128)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
>>> stack of 2.cause::javax.persistence.RollbackException: Error while committing the transaction
-> at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:92)
at org.olat.core.commons.persistence.DBImpl.commit(DBImpl.java:781)
at org.olat.group.manager.BusinessGroupServiceImpl.setLastUsageFor(BusinessGroupServiceImpl.java:327)
at org.olat.group.ui.run.BusinessGroupMainRunController.<init>(BusinessGroupMainRunController.java:235)
at org.olat.group.ui.BGControllerFactory.createRunControllerFor(BGControllerFactory.java:96)
at org.olat.group.BusinessGroupContextEntryControllerCreator.createController(BusinessGroupContextEntryControllerCreator.java:68)
at org.olat.NewControllerFactory.launch(NewControllerFactory.java:236)
at org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:202)
at org.olat.core.dispatcher.DispatcherAction.execute(DispatcherAction.java:154)
at org.olat.core.servlets.OLATServlet.doPost(OLATServlet.java:155)
at org.olat.core.servlets.OLATServlet.doGet(OLATServlet.java:128)
>>> stack of 3.cause::javax.persistence.OptimisticLockException: null
-> at org.hibernate.ejb.AbstractEntityManagerImpl.wrapStaleStateException(AbstractEntityManagerImpl.java:1413)
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1329)
at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1310)
at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:80)
at org.olat.core.commons.persistence.DBImpl.commit(DBImpl.java:781)
at org.olat.group.manager.BusinessGroupServiceImpl.setLastUsageFor(BusinessGroupServiceImpl.java:327)
at org.olat.group.ui.run.BusinessGroupMainRunController.<init>(BusinessGroupMainRunController.java:235)
at org.olat.group.ui.BGControllerFactory.createRunControllerFor(BGControllerFactory.java:96)
at org.olat.group.BusinessGroupContextEntryControllerCreator.createController(BusinessGroupContextEntryControllerCreator.java:68)
at org.olat.NewControllerFactory.launch(NewControllerFactory.java:236)
at org.olat.dispatcher.AuthenticatedDispatcher.execute(AuthenticatedDispatcher.java:202)
>>> stack of 4.cause::org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): org.olat.basesecurity.SecurityGroupMembershipImpl#20742524
-> at org.hibernate.persister.entity.AbstractEntityPersister.check(AbstractEntityPersister.java:2479)
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3189)
at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:3087)
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3416)
at org.hibernate.action.internal.EntityUpdateAction.execute(EntityUpdateAction.java:140)
at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:362)
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:354)
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:276)
at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:326)
at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:52)
at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1213)