Heartbeat timeout in BoundedSourceITCase.test[complex graph]

 13:32:03,156 [flink-akka.actor.default-dispatcher-39] WARN  org.apache.flink.runtime.taskmanager.Task                    [] - Source: Custom Source -> Timestamps/Watermarks (2/4)#0 (22326fea2054094646ad76acc0580001) switched from RUNNING to FAILED with failure cause: org.apache.flink.util.FlinkException: Disconnect from JobManager responsible for d80b19b767db5ec26d0a0f0d863cc046.
        at org.apache.flink.runtime.taskexecutor.TaskExecutor.disconnectJobManagerConnection(TaskExecutor.java:1663)
        at org.apache.flink.runtime.taskexecutor.TaskExecutor.disconnectAndTryReconnectToJobManager(TaskExecutor.java:1233)
        at org.apache.flink.runtime.taskexecutor.TaskExecutor.access$3900(TaskExecutor.java:183)
        at org.apache.flink.runtime.taskexecutor.TaskExecutor$JobManagerHeartbeatListener.lambda$handleJobManagerConnectionLoss$0(TaskExecutor.java:2384)
        at java.util.Optional.ifPresent(Optional.java:159)
        at org.apache.flink.runtime.taskexecutor.TaskExecutor$JobManagerHeartbeatListener.handleJobManagerConnectionLoss(TaskExecutor.java:2382)
        at org.apache.flink.runtime.taskexecutor.TaskExecutor$JobManagerHeartbeatListener.notifyHeartbeatTimeout(TaskExecutor.java:2365)
        at org.apache.flink.runtime.heartbeat.HeartbeatMonitorImpl.run(HeartbeatMonitorImpl.java:155)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at org.apache.flink.runtime.rpc.akka.AkkaRpcActor.lambda$handleRunAsync$4(AkkaRpcActor.java:455)
        at org.apache.flink.runtime.concurrent.akka.ClassLoadingUtils.runWithContextClassLoader(ClassLoadingUtils.java:68)
        at org.apache.flink.runtime.rpc.akka.AkkaRpcActor.handleRunAsync(AkkaRpcActor.java:455)
        at org.apache.flink.runtime.rpc.akka.AkkaRpcActor.handleRpcMessage(AkkaRpcActor.java:213)
        at org.apache.flink.runtime.rpc.akka.AkkaRpcActor.handleMessage(AkkaRpcActor.java:163)
        at akka.japi.pf.UnitCaseStatement.apply(CaseStatements.scala:24)
        at akka.japi.pf.UnitCaseStatement.apply(CaseStatements.scala:20)
        at scala.PartialFunction.applyOrElse(PartialFunction.scala:123)
        at scala.PartialFunction.applyOrElse$(PartialFunction.scala:122)
        at akka.japi.pf.UnitCaseStatement.applyOrElse(CaseStatements.scala:20)
        at scala.PartialFunction$OrElse.applyOrElse(PartialFunction.scala:171)
        at scala.PartialFunction$OrElse.applyOrElse(PartialFunction.scala:172)
        at scala.PartialFunction$OrElse.applyOrElse(PartialFunction.scala:172)
        at akka.actor.Actor.aroundReceive(Actor.scala:537)
        at akka.actor.Actor.aroundReceive$(Actor.scala:535)
        at akka.actor.AbstractActor.aroundReceive(AbstractActor.scala:220)
        at akka.actor.ActorCell.receiveMessage(ActorCell.scala:580)
        at akka.actor.ActorCell.invoke(ActorCell.scala:548)
        at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:270)
        at akka.dispatch.Mailbox.run(Mailbox.scala:231)
        at akka.dispatch.Mailbox.exec(Mailbox.scala:243)
        at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
        at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
        at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
        at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:175)
Caused by: java.util.concurrent.TimeoutException: The heartbeat of JobManager with id ca2daf271203710aef8ce4cc9dc394e5 timed out.
        ... 29 more