Possible NPE when shutting down RepositoryChangeBus in ModeShape 3

17:42:20,766 ERROR Error killing repository "testRepo": java.lang.NullPointerException
java.util.concurrent.ExecutionException: java.lang.NullPointerException
        at java.util.concurrent.FutureTask.report(FutureTask.java:122)
        at java.util.concurrent.FutureTask.get(FutureTask.java:188)
        at org.modeshape.jcr.TestingUtil.killRepository(TestingUtil.java:97)
        at org.modeshape.jcr.TestingUtil.killRepositories(TestingUtil.java:72)
        at org.modeshape.jcr.TestingUtil.killRepositories(TestingUtil.java:56)
        at org.modeshape.jcr.SingleUseAbstractTest.stopRepository(SingleUseAbstractTest.java:90)
        at org.modeshape.jcr.SingleUseAbstractTest.afterEach(SingleUseAbstractTest.java:111)
        at sun.reflect.GeneratedMethodAccessor81.invoke(Unknown Source)
        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.RunAfters.evaluate(RunAfters.java:33)
        at org.junit.rules.RunRules.evaluate(RunRules.java:20)
        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$2.evaluate(ParentRunner.java:229)
        at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
        at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
        at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
        at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:264)
        at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:153)
        at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:124)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray2(ReflectionUtils.java:208)
        at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:159)
        at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:87)
        at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:153)
        at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:95)
Caused by: java.lang.NullPointerException
        at org.modeshape.jcr.bus.RepositoryChangeBus$ChangeSetDispatcher.submit(RepositoryChangeBus.java:213)
        at org.modeshape.jcr.bus.RepositoryChangeBus.shutdown(RepositoryChangeBus.java:92)
        at org.modeshape.jcr.JcrRepository$RunningState.shutdown(JcrRepository.java:1643)
        at org.modeshape.jcr.JcrRepository.doShutdown(JcrRepository.java:434)
        at org.modeshape.jcr.JcrRepository$1.call(JcrRepository.java:343)
        at org.modeshape.jcr.JcrRepository$1.call(JcrRepository.java:340)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:724)