The instacnce need to be deleted from PS_AERUNCONTROL , PS_AETEMPTBLMGR, AERUNCONTROLPC.
PS_AETEMPTBLMGR controls the temp table locks. Also peoplesoft delivered Application engine AECLEANUP can also be used.
DELETE FROM PS_AETEMPTBLMGR WHERE PROCESS_INSTANCE = :1;
DELETE FROM PS_AERUNCONTROL...
How To release Temp table locks in Peoplesoft
