Issue Summary

This is reproducible on Data Center: yes

Similar to the initiative underway within the Jira Cloud to replace the Epic Link with Parent Link functionality.  Having the two different link types that behave different is a very confusing experience.

The Epic Link field does not respect the custom hierarchy that is set within Advanced Roadmaps, however the Issues in Epic field cannot be removed from the view, so it is possible to link new issues that are above the Epic in the hierarchy via the Epic link, but not in the Parent link. While these fields function correctly independently of each other, it is a very confusing user experience having both fields.
 

Steps to Reproduce

1. Create a new issue type
2. Within the Advanced Roadmaps Hierarchy (Settings > Manage Apps > Manage Apps > Hierarchy Configuration) set the new issue type above the Epic type.
3. Add the parent link field to the Epic and new issue type screen via (Settings > Issues > Screens).
4. Create a new Epic issue and load the issue.
5. Scroll down to the 'Issues in Epic' field and select the '+' to create a new issue in this Epic.
6. Make the new issue the type of the new issue type that is ranked above an Epic in the hierarchy.
7. Once the new issue is created and linked to the Epic, edit the Epic and select the new issue you just created and added to the Epic as a child as the parent link for the Epic.

Expected Results

The ability to link parent to child issues should respect the Advanced Roadmap hierarchy everywhere within Jira Data Center. The historical Epic Link functionality should be removed in favor using the Parent Link functionality.

Actual Results

The two fields act independently of each other. This can create very confusing scenarios as noted in the steps to recreate where circular logic could be created.

Workaround

Do not use the Epic issue type in projects where the Advanced Roadmaps hierarchy should be respected. Rather than using the built in Epic issue type, create a new Epic issue type and add that to the Advanced Roadmaps hierarchy. On this new issue type, include only the parent link field for users to create the parent child relationship.