PATCH / PUT API request voids custom field values for EPICs

Issue Summary

PATCH / PUT API request voids custom field values for EPICs

Steps to Reproduce

1. Login as Super Admin
2. Add custom field values of type "Custom Text Input"
3. In this example the fields are called as BPMS Code and Clarity Code
4. From the UI, create an EPIC and populate the custom field values with data
5. Create API request to update Owner

PATCH Request - https://<URL>/rest/align/api/2/epics/{Id} 
Request Body - [{"op": "replace","path": "/ownerId","value": "661721"}]
* Add the Id for recently created EPIC  in URL
Response Status Code - 204

PUT Request - https://<URL>/rest/align/api/2/epics/{Id}
Request Body - Add the relevant required fields for the EPIC along with Owner ID e.g. {"ownerId": "661721",}
* Add the Id for recently created EPIC  in URL
Response Status Code - 204

Actual Results

Both the API requests are successful in updating the owner but it voids the custom field values as created from the UI in step #4. This is evident from the audit log history.

Expected Results

The API request should only update the parameters part of the request body. The custom field values should be maintained as-is.

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available