[PRT.0101.9436] Dynamic Call Activity document list contains duplicate values for OutputPipelineName

Dears,

I’m facing the subject error while testing dynamic referenced process. Could you throw some lights.?

wM Version: 9.12

Use case:
I have three processes - say Parent, Child 1 and Child 2.
In the parent, I want to call Child 1 ‘n’ number of times i.e., a user task in Parent process has to ability to enter a list of names. For each name, I need to call Child 1 process in parallel (so can’t use loop) and queue a task to the name/user selected by Parent.
Now, this user in Child 1 process may now choose to complete the process or choose other names.
For each names selected by this user, I should call Child 2 process in parallel (so can’t use loop) and queue a task to the name/user selected by Child 1.

Implementation:
I have Child 2 process (BPMN, not wM referenced) which has a user task and few service tasks.
I have Child 1 process (BPMN, not wM referenced) which has a user task followed by a step to populate CallActivityModels for dynamic reference process of Child 2.
I have Parent process which has a user task followed by a step to populate CallActivityModels dynamic reference process of Child 1.

Upon build and deploy, when I execute the parent process, it fails with the error - [PRT.0101.9436] Dynamic Call Activity document list contains duplicate values for OutputPipelineName.

I’m populating the CallActivityModels as -
WaitForCallActivity - true
CallActivityModelId - Project/ProcessName
OutputPipelineName - name of the output document (not the fully qualified name)
InputPipelines - The input document

Note: All three processes have the same doc type but different names as inputs/outputs.