Thank you very much for your quick response!!!
I initialized the variable and appended it.
Then I added an approval task where the details of list item is assigned to our team for validation.

Once approved, the task is assigned to Manager for approval.

When I triggered the task, I got only one email as a admin (which is good sign).
But the flow skipped the Manager approval and completed the workflow.
There is no failure notification in the flow for me to check whats the issue.
Can you please shed some light as what am I missing?