Flink Python API java.io.EOFException - apache-flink

Question

I'm coding three Batch Applications, with the Python API, however, my third application is dealing with some Exceptions, especially when I increase the parallelism. This application has a Cross transformation inside it.
The cluster has 4 VMs, with 4 cpu cores and 7GB RAM each machine. So, the max parallelism setted 16.
The exception is:
org.apache.flink.client.program.ProgramInvocationException: The program execution failed: Job execution failed.
atorg.apache.flink.client.program.ClusterClient.run(ClusterClient.java:427)
at org.apache.flink.client.program.StandaloneClusterClient.submitJob(StandaloneClusterClient.java:101)
at org.apache.flink.client.program.ClusterClient.run(ClusterClient.java:400)
at org.apache.flink.client.program.ClusterClient.run(ClusterClient.java:387)
at org.apache.flink.client.program.ContextEnvironment.execute(ContextEnvironment.java:62)
at org.apache.flink.api.java.ExecutionEnvironment.execute(ExecutionEnvironment.java:926)
at org.apache.flink.python.api.PythonPlanBinder.runPlan(PythonPlanBinder.java:149)
at org.apache.flink.python.api.PythonPlanBinder.main(PythonPlanBinder.java:114)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.flink.client.program.PackagedProgram.callMainMethod(PackagedProgram.java:528)
at org.apache.flink.client.program.PackagedProgram.invokeInteractiveModeForExecution(PackagedProgram.java:419)
at org.apache.flink.client.program.ClusterClient.run(ClusterClient.java:339)
at org.apache.flink.client.CliFrontend.executeProgram(CliFrontend.java:831)
at org.apache.flink.client.CliFrontend.run(CliFrontend.java:256)
at org.apache.flink.client.CliFrontend.parseParameters(CliFrontend.java:1073)
at org.apache.flink.client.CliFrontend$2.call(CliFrontend.java:1120)
at org.apache.flink.client.CliFrontend$2.call(CliFrontend.java:1117)
at org.apache.flink.runtime.security.HadoopSecurityContext$1.run(HadoopSecurityContext.java:43)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:422)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1548)
at org.apache.flink.runtime.security.HadoopSecurityContext.runSecured(HadoopSecurityContext.java:40)
at org.apache.flink.client.CliFrontend.main(CliFrontend.java:1116)
Caused by: org.apache.flink.runtime.client.JobExecutionException: Job execution failed.
at org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$7.apply$mcV$sp(JobManager.scala:900)
at org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$7.apply(JobManager.scala:843)
at org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$7.apply(JobManager.scala:843)
at scala.concurrent.impl.Future$PromiseCompletingRunnable.liftedTree1$1(Future.scala:24)
at scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:24)
at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:40)
at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:397)
at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
Caused by: java.io.EOFException
at java.io.DataInputStream.readInt(DataInputStream.java:392)
at org.apache.flink.python.api.streaming.data.PythonStreamer.streamBufferWithoutGroups(PythonStreamer.java:252)
at org.apache.flink.python.api.functions.PythonMapPartition.mapPartition(PythonMapPartition.java:54)
at org.apache.flink.runtime.operators.MapPartitionDriver.run(MapPartitionDriver.java:103)
at org.apache.flink.runtime.operators.BatchTask.run(BatchTask.java:490)
at org.apache.flink.runtime.operators.BatchTask.invoke(BatchTask.java:355)
at org.apache.flink.runtime.taskmanager.Task.run(Task.java:655)
at java.lang.Thread.run(Thread.java:745)
I've got some evidences:
1) It's not at all deterministic, eventually, the application finished without errors.
2) With parallelism <= 4 the algorithm finish flawlessly, exception often happens with higher parallelism degrees.
3) Even entering small inputs (~20MB) the exception occurr.
4) I didn't find any error at the slaves logs (jobmanager), only at the Master Flink Taskmanager
Can you help to find out the responsible for this? I can get more logs (namenode, datanode, jobmanager, taskmanager) if necessary.