You did not mention the nonSQL db you were accessing.  Also, how long is it hanging?  Have you tried setting/varying parameter "fetch buffer size"?  Have you tried splitting the data pump task into 2 tasks (nonSQL db table -> file -> SQL db table)?

I experienced the same hang/stall at the end of a data pump task from a nonSQL db table (Oracle/Rdb) into a SQL db table.  The stall time was more significant in larger nonSQL tables, but as a percentage of time of the task run time it was fairly small and the task did eventually complete.

Jeff