C2C migration of a single project creates duplicated custom fields with (migrated) in their name

Issue Summary

When migrating a single project to a site the first time using C2C method, a new custom field will be created with (migrated) appended in their name.

This is reproducible on Data Center: N/A

Steps to Reproduce

1. Choose a destination site where C2C migration has not been performed yet.
2. In the source site, select a project and perform a C2C migration to the destination site. 
3. Go to Settings > Issues > Custom fields 

Expected Results

If the custom field in the source and the destination sites have the same name, and underlying properties, they should be merged in one custom field to avoid unnecessary duplicates. 

Actual Results

If the custom field in the source and the destination sites have the same name, and underlying properties, a new custom field is still created in the destination site with (migrated) appended on the name. 

Workaround

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