Error: is not the most recent version of this flow file within this session

[Sumanth Chinthagunta]

I am creating a new flowFile in my processor’s onTrigger method and getting 
following error!
Please advice if I am doing anything wrong …..

My requirement is: I need to create a new outgoing flowFile with a set of 
derived  attributes and route to success path.  
 
```groovy
public void onTrigger(ProcessContext context, ProcessSession session) throws 
ProcessException {
FlowFile ff =  session.create()
session.putAllAttributes(ff,[summ:'demo'])
session.transfer(ff, REL_SUCCESS);
}
```
org.apache.nifi.processor.exception.FlowFileHandlingException: 
FlowFile[0,54356692392022.mockFlowFile,131B] is not the most recent version of 
this flow file within this session

Thanks 
Sumanth