The workflow process generated by completing shipment ran for over 40 minutes and had to be aborted by user.
The particular Shipment contains around 330 lines, is it possible there might be a threshold as to how many workflow process/activities can be running?
We suspect this was happening when more than 1 user tried to complete a large shipments at almost the same time.
Once these 'running' process been stopped and tried completing these shipments again, the work flow seems to complete normally.
Message taken debug screen is shown below:
OnlineHelp.Worker.run (e) java.lang.NullPointerException
-----------> MInOut.lock: failed 
-----------> MWorkflow.startWait: Timeout after sec 15 
-----------> MLookup.run: AD_WF_Process.AD_WF_Process_ID: Loader - Too many records