I see 2 commits in 6.1.0 to address NPEs in this class but I'm not sure if either of those cover this particular NPE.  I'm unable to reproduce this issue with my code after the first occurrence.  Does anyone know if this has been fixed in 6.1.0? Please let me know if I can provide additional info or if I should open a defect in Jira.

Thanks,
David

Here is the stack trace:
java.lang.NullPointerException
        at
org.drools.core.common.LeftTupleSetsImpl.removeUpdate(LeftTupleSetsImpl.java:172)
        at
org.drools.core.common.LeftTupleSetsImpl.addDelete(LeftTupleSetsImpl.java:84)
        at
org.drools.core.common.SynchronizedLeftTupleSets.addDelete(SynchronizedLeftTupleSets.java:20)
        at
org.drools.core.reteoo.LeftInputAdapterNode.doDeleteSegmentMemory(LeftInputAdapterNode.java:339)
        at
org.drools.core.reteoo.LeftInputAdapterNode.doDeleteObject(LeftInputAdapterNode.java:301)
        at
org.drools.core.reteoo.LeftInputAdapterNode.retractLeftTuple(LeftInputAdapterNode.java:417)
        at
org.drools.core.reteoo.ObjectTypeNode.doRetractObject(ObjectTypeNode.java:352)
        at
org.drools.core.reteoo.ObjectTypeNode.retractObject(ObjectTypeNode.java:335)
        at
org.drools.core.reteoo.EntryPointNode.retractObject(EntryPointNode.java:395)
        at
org.drools.core.common.NamedEntryPoint.delete(NamedEntryPoint.java:605)
        at
org.drools.core.common.AbstractWorkingMemory.delete(AbstractWorkingMemory.java:1184)
        at
org.drools.core.common.AbstractWorkingMemory.delete(AbstractWorkingMemory.java:1176)
        at
org.drools.core.impl.StatefulKnowledgeSessionImpl.delete(StatefulKnowledgeSessionImpl.java:316)