Last stage of request set does not complete

Hi,

There are a couple of request sets that used to run without any issues for months until last week. We observed the last stage within these request sets stays in Running-Normal state for hours and user has to terminate them manually. The main request set as well the stage that was terminated do not generate any log/output file. For one of these sets, when user sets the 'Run Alone' parameter to 'Yes', the request set gets completed successfully. However, we are unable to determine the root cause of the original problem wherein the stage remains running-normal. Can you please advise?