UI GroupComparatorHelper in admin ui gives these errors occasionally (not sure how to reproduce)

2013-04-26 15:07:40,719: [TP-Processor8] ERROR DefaultComparatorImpl.getComparisonString(129) - error for obj: class edu.internet2.middleware.grouper.ui.util.SubjectPrivilegeAsMap
java.lang.IllegalArgumentException: {typeName=, id=, description=, subject=

{typeName=group, id=bea61be19fc54afab4ab1536e5731f9a, description=User group for google sub-domain dev3, name=penn:isc:nandt:apps:dev3.gapps.upenn.edu:user, subjectId=bea61be19fc54afab4ab1536e5731f9a, subjectType=group, sourceId=g:gsa}

, name=, privilege=READ, type=access, groupOrStem=

{desc=xtabi, typeOfGroupDb=group, alternateNameDb=testdd:seas:wsk:xtabi, extensionDb=xtabi, displayNameDb=test:seas:wsk:xtabi, stemId=ab71be67-359c-44ea-b9d9-03049426840b, id=8b5ade16-5963-4796-aed3-97f324d18c66, nameDb=test:seas:wsk:xtabi, description=test group X, isGroup=true, name=test:seas:wsk:xtabi, parentStemName=test:seas:wsk, subjectType=group, displayExtensionDb=xtabi, descriptionDb=test group X, parentUuid=ab71be67-359c-44ea-b9d9-03049426840b, extension=xtabi, contextId=446aad7f2b9b4504b3b24accd7b0aeeb, groupId=8b5ade16-5963-4796-aed3-97f324d18c66, displayExtension=xtabi, subjectId=8b5ade16-5963-4796-aed3-97f324d18c66, modifierUuid=069f0c95-f5c3-42ae-873d-9da09b60f8e7, creatorUuid=934435c2-ac7b-4cde-ac24-d3035ba47cb3, uuid=8b5ade16-5963-4796-aed3-97f324d18c66, group=Group[name=test:seas:wsk:xtabi,uuid=8b5ade16-5963-4796-aed3-97f324d18c66], displayName=test:seas:wsk:xtabi}

, sourceId=} is not a Group
at edu.internet2.middleware.grouper.ui.GroupComparatorHelper.getComparisonString(GroupComparatorHelper.java:81)
at edu.internet2.middleware.grouper.ui.DefaultComparatorImpl.getComparisonString(DefaultComparatorImpl.java:126)
at edu.internet2.middleware.grouper.ui.DefaultComparatorImpl.compare(DefaultComparatorImpl.java:117)
at java.util.Arrays.mergeSort(Arrays.java:1270)
at java.util.Arrays.mergeSort(Arrays.java:1282)
at java.util.Arrays.mergeSort(Arrays.java:1282)
at java.util.Arrays.mergeSort(Arrays.java:1282)
at java.util.Arrays.sort(Arrays.java:1210)
at java.util.Collections.sort(Collections.java:159)
at edu.internet2.middleware.grouper.ui.actions.LowLevelGrouperCapableAction.sort(LowLevelGrouperCapableAction.java:630)
at edu.internet2.middleware.grouper.ui.actions.PopulateSubjectSummaryAction.grouperExecute(PopulateSubjectSummaryAction.java:504)
at edu.internet2.middleware.grouper.ui.actions.GrouperCapableAction$1.callback(GrouperCapableAction.java:232)
at edu.internet2.middleware.grouper.internal.dao.hib3.Hib3TransactionDAO$1.callback(Hib3TransactionDAO.java:66)
at edu.internet2.middleware.grouper.hibernate.HibernateSession.callbackHibernateSession(HibernateSession.java:571)
at edu.internet2.middleware.grouper.internal.dao.hib3.Hib3TransactionDAO.transactionCallback(Hib3TransactionDAO.java:56)
at edu.internet2.middleware.grouper.hibernate.GrouperTransaction.callbackGrouperTransaction(GrouperTransaction.java:87)
at edu.internet2.middleware.grouper.hibernate.GrouperTransaction.callbackGrouperTransaction(GrouperTransaction.java:106)
at edu.internet2.middleware.grouper.ui.actions.GrouperCapableAction.grouperTransactionExecute(GrouperCapableAction.java:229)
at edu.internet2.middleware.grouper.ui.actions.GrouperCapableAction.execute(GrouperCapableAction.java:294)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:439)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:241)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:397)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at edu.internet2.middleware.grouper.ui.LoginCheckFilter$1.callback(LoginCheckFilter.java:188)
at edu.internet2.middleware.grouper.GrouperSession.callbackGrouperSession(GrouperSession.java:801)
at edu.internet2.middleware.grouper.ui.LoginCheckFilter.doFilter(LoginCheckFilter.java:183)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at edu.internet2.middleware.grouper.ui.ErrorFilter.doFilter(ErrorFilter.java:147)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at edu.internet2.middleware.grouper.ui.GrouperUiFilter.doFilter(GrouperUiFilter.java:822)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:190)
at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:283)
at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:767)
at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:697)
at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:889)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:690)
at java.lang.Thread.run(Thread.java:619)