Major issue with the ExecuteScript using Python in release 1.13.2

Hi,

I have downloaded the latest version of Nifi 1.13.2. In one of my flows Im using an Execute script processor that utilizes python engine  which I know it was working without problems in an older (version 1.11.4). I noticed when the processor executes for the first time it works then if you stop it and re run again it hangs and the flow files get stuck in the upstream queue. Initially I thought something in my script  is causing the issue  so I change it to something as simple as this 

flowFile = session.get()
if flowFile != None:
     # All processing code starts at this indent
     session.transfer(flowFile, REL_SUCCESS)

Even with this simple script the processor hangs and the flow files remain in the queue. This is a major issue and its causing me not to upgrade. Not sure if you are aware of it and if if there is anything that can be done to mitigate. please advise.