I have created automation script to sum the Original Estimates from the Sub Tasks and update the value into "Original Estimates" field in the Parent User Story
Somehow, its not summing total of original estimate from sub-tasks into the Original estimate field in user story, when I update the original estimate or any other field in sub-task, not sure where I am missing
. Can you please help to identify the problem.

I have attached the Automation Rule and the Audit log as well for your reference.
Note: I have read through posts with similar issue and that has helped me to reach what I have done now.