First reporter name being replaced in Activity Tab after change to new reporter

From https://jira.atlassian.com/browse/JRA-4618, we know that when reporter differs from creator, the creator did not recorded in change history. However, user thoughts that after create issue then only edit the reporter in activity tab, JIRA should able record it. However, JIRA replaced the first reporter name to new reporter name and it seem user no longer able to keep track the data in JIRA activity.

Steps to reproduce the problem:

1. Create an issue without changing the reporter.
2. In activity tab showing the first reporter 'admin':
   
3. After issue created, go edit the reporter name from 'admin' to 'ckl'.
4. In activity tab, the first reporter has been replace to 'ckl'.