Unable to pass the parameters between playbooks in google conversational agents

[vikram_6174]

Question/problem: while trying to pass the parameters extracted from an OPEN API tool in a child playbook to a parent playbook it is unable to do so, in the trace debug it is showing up as " error unable to parse" and in the original response, the "actionParameters" for playbook output is null despite defining in examples and in the output parameters of child playbook.

Parent playbook - Order Status:
starting instructions where it calls the child playbook to retrieve user order history and username 

example defined :

user order history playbook expanded :

defined output parameters that needs to be passed to the parent playbook.

Child playbook : User Order History

Instructions provided :

example provided to the playbook:

parameters that child playbook returns are defined under the parameters tab in child playbook as below.

During the conversation as below :

The tool is getting the output properly but the child playbook is unable to emit out through the output parameters during the conversation as defined in the example.

 
Error messages :
In debug trace 

IN original response :

The tool output is 200 status 

but the playbook outputActionParameters is empty due to which the error is occurring.

Can you please tell me where it is going wrong ,I have read the documentation but didn't find anything helpful, I followed whatever they mentioned in it.
Any help or lead would be much appreciated.