Reproducer at: https://github.com/DuncanDoyle/DroolsPhreakIssues

Clone the project in the given GitHub repository and run 'mvn -Pphreak clean test' (-Pphreak runs the test with PHREAK, -Preteoo runs the test with ReteOO).

Note that the 'testRG_FLT_03_Two' is intended to fail because, as you can see from the comments in the testcode and the .drl, the logic of the rule is actually wrong. However, it does force
the PHREAK engine to throw a ClassCastException every now and then. Note: not always (it might actually takes a number of test runs to reproduce the ClassCastException. It seems to depend on
how many events you enter into the system in one batch ....)!!

Sometimes 'testRG_FLT_03_Two' fails, with:

Failed tests: testRG_FLT_03_Two(org.jboss.ddoyle.drools.sample.PhreakyTest): Two last event must be in working memory expected:<12> but was:<1>

and sometimes it throws:

<error message="org.drools.core.reteoo.EvalNodeLeftTuple cannot be cast to org.drools.core.reteoo.RuleTerminalNodeLeftTuple" type="java.lang.ClassCastException">java.lang.ClassCastException: org.drools.core.reteoo.EvalNodeLeftTuple cannot be cast to org.drools.core.reteoo.RuleTerminalNodeLeftTuple
at org.drools.core.phreak.PhreakRuleTerminalNode.doLeftTupleUpdate(PhreakRuleTerminalNode.java:155)
at org.drools.core.phreak.PhreakBranchNode.doLeftUpdates(PhreakBranchNode.java:153)
at org.drools.core.phreak.PhreakBranchNode.doNode(PhreakBranchNode.java:31)
at org.drools.core.phreak.RuleNetworkEvaluator.innerEval(RuleNetworkEvaluator.java:364)
at org.drools.core.phreak.RuleNetworkEvaluator.outerEval(RuleNetworkEvaluator.java:162)
at org.drools.core.phreak.RuleNetworkEvaluator.evaluateNetwork(RuleNetworkEvaluator.java:117)
at org.drools.core.phreak.RuleExecutor.reEvaluateNetwork(RuleExecutor.java:199)
at org.drools.core.phreak.RuleExecutor.evaluateNetworkAndFire(RuleExecutor.java:66)
at org.drools.core.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:927)
at org.drools.core.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1187)
at org.drools.core.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:957)
at org.drools.core.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:931)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:233)
at org.jboss.ddoyle.drools.sample.PhreakyTest.testFrequencyTwo(PhreakyTest.java:91)
at org.jboss.ddoyle.drools.sample.PhreakyTest.testRG_FLT_03_Two(PhreakyTest.java:62)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:53)
at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:123)
at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:104)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:164)
at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:110)
at org.apache.maven.surefire.booter.SurefireStarter.invokeProvider(SurefireStarter.java:175)
at org.apache.maven.surefire.booter.SurefireStarter.runSuitesInProcessWhenForked(SurefireStarter.java:107)
at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:68)
</error>

The behaviour seems a bit random (which concerns me as well, as ReteOO was deterministic and would produce the same results on every test). Note that if I remove the
conditional named consequence construct and split the rule into 2 rules, the behaviour of PHREAK seems deterministic and I get this, expected, error (which is the same error I get with ReteOO):

Failed tests: testRG_FLT_03_Two(org.jboss.ddoyle.drools.sample.PhreakyTest): Two last event must be in working memory expected:<12> but was:<30>