DB-API (asynchronous) hangs

During an asynchronous sql I noticed my python application hung after "...Stage-2 map = 100%, reduce = 0%, Cumulative CPU 10.58 sec" , in my application's log file. I see the reduce job listed as 0%.

But when I looked at the job in hadoop, it shows it finished successfully - both map & reduce finished successfully. The python application seats on a different machine (cloud vm) from the hdfs/hadoop environment (on-prem vm). Anything else I should be checking in my try-except block?