Picketlink: PLFED000092 Null value error in logs

Issue

We see about 40 of these Picketlink errors in the logs daily. What does it mean? How can we fix it?

ERROR [org.apache.catalina.connector.CoyoteAdapter] (http-executor-threads - 56) An exception or error occurred in the container during the request processing: javax.servlet.ServletException: java.lang.RuntimeException: PLFED000092: Null Value: Destination
    at org.picketlink.identity.federation.bindings.tomcat.idp.AbstractIDPValve.processSAMLResponseMessage(AbstractIDPValve.java:796) [picketlink-jbas7-2.1.3.1-redhat-1.jar:2.1.3.1-redhat-1]
    at org.picketlink.identity.federation.bindings.tomcat.idp.AbstractIDPValve.invoke(AbstractIDPValve.java:386) [picketlink-jbas7-2.1.3.1-redhat-1.jar:2.1.3.1-redhat-1]
    at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:169) [jboss-as-web-7.1.3.Final-redhat-4.jar:7.1.3.Final-redhat-4]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.17.Final-redhat-1.jar:]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.17.Final-redhat-1.jar:]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.17.Final-redhat-1.jar:]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:372) [jbossweb-7.0.17.Final-redhat-1.jar:]
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [jbossweb-7.0.17.Final-redhat-1.jar:]
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:679) [jbossweb-7.0.17.Final-redhat-1.jar:]
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:519) [jbossweb-7.0.17.Final-redhat-1.jar:]
    at org.jboss.threads.SimpleDirectExecutor.execute(SimpleDirectExecutor.java:33)
    at org.jboss.threads.QueueExecutor.runTask(QueueExecutor.java:801)
    at org.jboss.threads.QueueExecutor.access$100(QueueExecutor.java:45)
    at org.jboss.threads.QueueExecutor$Worker.run(QueueExecutor.java:842)
    at java.lang.Thread.run(Unknown Source) [rt.jar:1.7.0_09]
    at org.jboss.threads.JBossThread.run(JBossThread.java:122)
Caused by: java.lang.RuntimeException: PLFED000092: Null Value: Destination
    at org.picketlink.identity.federation.PicketLinkLoggerImpl.nullValueError(PicketLinkLoggerImpl.java:106) [picketlink-jbas7-2.1.3.1-redhat-1.jar:2.1.3.1-redhat-1]
    ... 16 more