Default value not working for the phone number field

Problem/Motivation

The default value is not working properly if only changing the country code from default to something else and remain the Phone number field as it is. If we provide both the values Country code, Phone number then the default value is getting updated. But I want to set default country code in this case its not updating the default value with the country code we are providing.

NOTE: If we are only updating the country code for this field from Manage form display its changing the default value in the field edit page (/admin/structure/types/manage/{bundle_name}/fields/node.{bundle_name}.{field_machine_name}). So I think it should update the default value from the field edit page also.

Attached a screenshot -

Steps to reproduce

1. Add new field of Phone number type
2. Change only the country code in Default Value section
3. Save the field
4. Edit the same field and check if the default value is same as before or its updated with the value we have provided