Issue Summary

Duplicate user keys were encountered during Jira import

Environment

• Jira Cloud

Steps to Reproduce

1. Import Jira backup from another Cloud instance

Expected Results

Import completes succesfully

Actual Results

Import fails with the following error in the UI:

There was an error importing file jira-export-modified.zip: Validation failed. Following issues were reported:
Duplicate user keys were encountered: <userA>, <userB>, <userC>, etc

A similar error shows in the logs:

2019-01-10 18:27:14.974	WARN	com.atlassian.jira.plugin.backup.ImportValidationTaskRunner	Import validation failed: Duplicate user keys were encountered: <userA>, <userB>, <userC>, etc	 	 

Notes

Seems to be affecting Cloud -> Cloud migrations
Also seems to be related to case-insensitivity, importer is seeing user keys like userA and usera being the same

Workaround

Edit the entities.xml file and update the duplicate user keys so that they are unique.
The lines you need to edit will start with the following string:

<ApplicationUser id=