Java SDK Harness throws NPE for VoidCoder as key coder

java.lang.NullPointerException
	at org.apache.beam.model.fnexecution.v1.BeamFnApi$StateKey$BagUserState$Builder.setKey(BeamFnApi.java:39390)
	at org.apache.beam.fn.harness.state.FnApiStateAccessor.createBagUserStateKey(FnApiStateAccessor.java:444)
	at org.apache.beam.fn.harness.state.FnApiStateAccessor.bindValue(FnApiStateAccessor.java:195)
	at org.apache.beam.sdk.state.StateSpecs$ValueStateSpec.bind(StateSpecs.java:327)
	at org.apache.beam.sdk.state.StateSpecs$ValueStateSpec.bind(StateSpecs.java:317)
	at org.apache.beam.fn.harness.FnApiDoFnRunner$ProcessBundleContext.state(FnApiDoFnRunner.java:1432)
	at org.apache.beam.sdk.transforms.ParDoTest$TimerTests$TwoTimerTest$1$DoFnInvoker.invokeProcessElement(Unknown Source)
	at org.apache.beam.fn.harness.FnApiDoFnRunner.processElementForParDo(FnApiDoFnRunner.java:740)
	at org.apache.beam.fn.harness.FnApiDoFnRunner.access$700(FnApiDoFnRunner.java:132)
	at org.apache.beam.fn.harness.FnApiDoFnRunner$Factory.lambda$createRunnerForPTransform$1(FnApiDoFnRunner.java:203)
	at org.apache.beam.fn.harness.data.PCollectionConsumerRegistry$MetricTrackingFnDataReceiver.accept(PCollectionConsumerRegistry.java:216)
	at org.apache.beam.fn.harness.data.PCollectionConsumerRegistry$MetricTrackingFnDataReceiver.accept(PCollectionConsumerRegistry.java:179)
	at org.apache.beam.fn.harness.BeamFnDataReadRunner.forwardElementToConsumer(BeamFnDataReadRunner.java:204)
	at org.apache.beam.fn.harness.data.QueueingBeamFnDataClient.drainAndBlock(QueueingBeamFnDataClient.java:106)
	at org.apache.beam.fn.harness.control.ProcessBundleHandler.processBundle(ProcessBundleHandler.java:295)
	at org.apache.beam.fn.harness.control.BeamFnControlClient.delegateOnInstructionRequestType(BeamFnControlClient.java:173)
	at org.apache.beam.fn.harness.control.BeamFnControlClient.lambda$processInstructionRequests$0(BeamFnControlClient.java:157)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)