10D

Explanation
A job step task abnormally ended, but it had a
subtask with a status of step must complete (MC). This completion
code is found only in the job step task.

System action
The system abnormally ends the subtask. The system
sends messages about the problem to the job log.

System programmer response
  Find the abend code for the task
that attached the abended subtask in: Messages in the job log
The logrec data set error record
The TCBCMP field of the task control block (TCB) for the attaching
task, if a dump is available

 Diagnose the original abend in the attaching task.

Source
Recovery termination manager (RTM)