Service Managers and Internal Manager keep restarting

Hi Gurus,

We have issue in our 11.5.10.2 instance that 2 of our Service managers keep restarting, and the Internal Manager also keep restarting.
From the ICM Log what I can see is below message :

=========================================

Shutting down Internal Concurrent Manager : 19-FEB-2016 12:28:18

The sgpehr1_0219@sgpehr1 internal concurrent manager has terminated successfully - exiting.

mailto=

          restart=N

             diag=N

            sleep=60 (default)

             pmon=20 (default)

           quesiz=1  (default)

Found dead process: spid=(25044), cpid=(1038567), ORA pid=(69), manager=(0/1)

===========================================

It seems the process that "dead" is actually the ICM process it self then it keep spawning.

We did bounced the ICM for few times, but the issue still there. Although it doesn't affect to any CP jobs, CM still pick up the request and its all completed normal.