Issue Summary

Renaming Epic issue type in next-gen projects breaks the import CSV function of normal tasks when mapping the issue key

Steps to Reproduce

1. In a team-managed project rename the Epic issue type
2. try to import the CSV file via import from external system
3. Select summary and issue key
4. Jira will not you import any issues unless the stories have a parent Epic.
   
5. rename back the issue type to Epic and Epic to one issue
6. importing CSV file will clear the Parent of all the imported stories!!
   

Expected Results

Jira should allow you to import stories without parents when you rename the Epic.

Actual Results

Renaming Epic issue type breaks the import of issues via CSV file
Here is the video
https://jira.atlassian.com/secure/attachment/410391/demo_parent_issue.mp4

Workaround

Imports that don't map the issue key continue to work.
Importing csv via the Advanced Search screen continues to work