Issue:

CSV export for the worklog contains the lower username of the user.
Importing the issues to a different instance causes the worklog to be added by an anonymous user.

Steps to reproduce:

1. Log work on a Jira issue
2. CSV export the issue with all fields
3. In the CSV file notice that you'll see the lower username as the author of the worklog
4. CSV import issue to another instance with summary and map the worklog field
5. Notice the user is anonymous in the work logged

Expected Result:

CSV export for the worklog should contain the Atlassian Account ID just like the author of the comments.

Actual Result:

CSV export contains the lower username and it results in anonymous worklog entries when imported to another instance.

Workaround:

Replace the lower username with the Atlassian account ID of the user.