NullPointerException in FromNode.destroyCreatedHandles

I received this NullPointerException after upgrading to drools 5.1.1. The NullPointerException is being thrown when the rule executes "update($build);" where $build is set in the LHS from a Build in working memory. I'm not sure if the bug is that matches may be null and a null check needs to be added or if something else is going on causing the tuple to not be found.

Caused by: java.lang.NullPointerException
at org.drools.reteoo.FromNode.destroyCreatedHandles(FromNode.java:336)
at org.drools.reteoo.FromNode.retractLeftTuple(FromNode.java:326)
at org.drools.reteoo.CompositeLeftTupleSinkAdapter.doPropagateRetractLeftTuple(CompositeLeftTupleSinkAdapter.java:238)
at org.drools.reteoo.CompositeLeftTupleSinkAdapter.propagateRetractRightTuple(CompositeLeftTupleSinkAdapter.java:155)
at org.drools.reteoo.JoinNode.retractRightTuple(JoinNode.java:151)
at org.drools.reteoo.ModifyPreviousTuples.retractTuples(ModifyPreviousTuples.java:126)
at org.drools.reteoo.EntryPointNode.modifyObject(EntryPointNode.java:176)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1442)
at org.drools.common.AbstractWorkingMemory.update(AbstractWorkingMemory.java:1349)
at org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:183)
at org.drools.base.DefaultKnowledgeHelper.update(DefaultKnowledgeHelper.java:196)
at buildSchedulerV2.Rule_Combine_Builds_0.defaultConsequence(Rule_Combine_Builds_0.java:36)
at buildSchedulerV2.Rule_Combine_Builds_0DefaultConsequenceInvoker.evaluate(Rule_Combine_Builds_0DefaultConsequenceInvoker.java:49)
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:917)