Root Cause: The sub-workflow does not get the correct end status.
Update to a fix version listed below or a newer version if available.
Fix Status: Released
Component(s): AE Server and Initialdata
Automation Engine 12.1.0 - Available
Automation Engine 12.0.2 - Available
Automation Engine 11.2.5 - Available
Cancel the sub-workflow manually.
If the sub-workflow is added before starting the master workflow, it will result in the sub-workflow ending with an ENDED_EMPTY status and the master workflow finishes with as status of ENDED_OK.