Error when closing session in IndexingThread

During mass indexing from nuxeo-shell.

02:47:04,136 ERROR [IndexingThreadImpl] Error when cleaning CoreSession bound to indexing thread
java.lang.reflect.UndeclaredThrowableException
at $Proxy274.getSessionId(Unknown Source)
at org.nuxeo.ecm.core.search.threading.IndexingThreadImpl.closeCoreSession(IndexingThreadImpl.java:111)
at org.nuxeo.ecm.core.search.threading.IndexingThreadImpl.finalize(IndexingThreadImpl.java:157)
at java.lang.ref.Finalizer.invokeFinalizeMethod(Native Method)
at java.lang.ref.Finalizer.runFinalizer(Finalizer.java:83)
at java.lang.ref.Finalizer.access$100(Finalizer.java:14)
at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:160)
Caused by: java.io.IOException: org/jboss/ejb3/stateful/StatefulRemoteInvocation
at org.jboss.serial.classmetamodel.ClassMetamodelFactory.getClassMetaData(ClassMetamodelFactory.java:332)
at org.jboss.serial.classmetamodel.StreamingClass.readStream(StreamingClass.java:72)
at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.readObjectDescriptionFromStreaming(ObjectDescriptorFactory.java:381)
at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.objectFromDescription(ObjectDescriptorFactory.java:82)
at org.jboss.serial.objectmetamodel.DataContainer$DataContainerInput.readObject(DataContainer.java:845)
at org.jboss.serial.io.MarshalledObjectForLocalCalls.get(MarshalledObjectForLocalCalls.java:60)
at org.jboss.ejb3.remoting.IsLocalInterceptor.invoke(IsLocalInterceptor.java:56)
at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
at org.jboss.ejb3.stateful.StatefulRemoteProxy.invoke(StatefulRemoteProxy.java:133)
... 7 more
Caused by: java.lang.ClassNotFoundException: org/jboss/ejb3/stateful/StatefulRemoteInvocation
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:242)
at org.jboss.serial.classmetamodel.ClassMetamodelFactory.resolveClassByName(ClassMetamodelFactory.java:274)
at org.jboss.serial.classmetamodel.ClassMetamodelFactory.getClassMetaData(ClassMetamodelFactory.java:289)
... 15 more

This seem to be very new ...