Subprocess Caching - Nullpointer Exception

Hi, 

I built a simple process with a suprocess(caching) in the beginning where simply I pull data from a database. 
When I start executing the process I get an error: Process failed with the following message: 

 Exception: java.lang.NullPointerException

• Message: null
• Stack trace:
• com.rapidminer.extension.operator_toolbox.operator.utility.CachingSubprocess.hashEmbeddedProcess(CachingSubprocess.java:315)
• com.rapidminer.extension.operator_toolbox.operator.utility.CachingSubprocess.doWork(CachingSubprocess.java:217)
• com.rapidminer.operator.Operator.execute(Operator.java:1023)
• com.rapidminer.operator.execution.SimpleUnitExecutor.execute(SimpleUnitExecutor.java:77)
• com.rapidminer.operator.ExecutionUnit$2.run(ExecutionUnit.java:805)
• com.rapidminer.operator.ExecutionUnit$2.run(ExecutionUnit.java:800)
• java.security.AccessController.doPrivileged(Native Method)
• com.rapidminer.operator.ExecutionUnit.execute(ExecutionUnit.java:800)
• com.rapidminer.operator.OperatorChain.doWork(OperatorChain.java:423)
• com.rapidminer.operator.Operator.execute(Operator.java:1023)
• com.rapidminer.Process.executeRoot(Process.java:1464)
• com.rapidminer.Process.lambda$executeRootInPool$5(Process.java:1443)
• com.rapidminer.studio.concurrency.internal.AbstractConcurrencyContext$AdaptedCallable.exec(AbstractConcurrencyContext.java:362)
• java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
• java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
• java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
• java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:175)

I had this a couple of times but I am slowly getting tired of this. 

Can you fix this bug in the operator toolbox extension or help if you know how I can fix this in my process or setup?