Error in JMS event handling of certificate changes in assessment main controller

2015-01-05 09:54:09,313 [ActiveMQ Session Task] ERROR EventAgency  - OLAT::ERROR ^%^ N40-E1
Error while sending generic event! Removing listener: org.olat.course.assessment.AssessmentMainController [cListener:org.olat.course.run.CourseRuntimeController, ]
>>>stack of 1.cause::java.lang.UnsupportedOperationException: null
-> at java.util.AbstractMap.put(Unknown Source)
   at org.olat.course.assessment.AssessedIdentitiesTableDataModel.putCertificate(AssessedIdentitiesTableDataModel.java:152)
   at org.olat.course.assessment.AssessmentMainController.updateCertificate(AssessmentMainController.java:653)
   at org.olat.course.assessment.AssessmentMainController.event(AssessmentMainController.java:644)
   at org.olat.core.util.event.EventAgency$1.run(EventAgency.java:102)
   at org.olat.core.logging.activity.ThreadLocalUserActivityLoggerInstaller.runWithUserActivityLogger(ThreadLocalUserActivityLoggerInstaller.java:108)
   at org.olat.core.util.event.EventAgency.fireEvent(EventAgency.java:100)
   at org.olat.core.util.event.AbstractEventBus.doFire(AbstractEventBus.java:93)
   at org.olat.commons.coordinate.cluster.jms.ClusterEventBus.serveMessage(ClusterEventBus.java:352)
   at org.olat.commons.coordinate.cluster.jms.ClusterEventBus.onMessage(ClusterEventBus.java:273)
   at org.apache.activemq.ActiveMQMessageConsumer.dispatch(ActiveMQMessageConsumer.java:1204)