Hi Ankur,

Our scenario is like below:

# The Change Management Outage tab must display an option to create and link a New CI Outage record via a GUI new button.

# When clicked, must launch a New CI Outage record entry window
# When Saved, must automatically link and relate the Outage record to the CHG record

Here what ServiceNow suggests us through KB is below

https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0790306

Cause:
The Outage related list on the Change Request form by default only lets you Edit (add/remove existing records) items in the list.
When the New UI action is enabled and used to create outages, it results in duplicate outages being associated to that Change.
Essentially:
The outage form by design creates a record and links it to the task specified.
The related list New button creates a record and links it to the parent record.

Resolution:
Instead of enabling the New UI Action on the Outages related list, use the Create Outage UI Action from the Task-Outage Relationship plugin.

Please help me out

Thanks

Venkat