We came across some weird behavior of DAC -
The production Execution Plan failed but when looked into details actually none of the Tasks was failed and all pending tasks were in 'Stopped' state.
One more thing to add - All Predecessors for these Stopped tasks were completed.
Normally in production we never faced this issue before and Its as of now one off case... but is this expected .... and yes, is there any long term solution available.
Our Short term solution was - Restart the execution plan. It worked well.
DAC version - 188.8.131.52.4.20141119.2119