Renaming agent username breaks Agent's issues in progress jql query

Summary

Username rename will break the jql query used to retrieve an agent's issues in progress on the Servicedesk Agent's page

Steps to Reproduce

1. Change the username of an agent that has been assigned tickets in Service Desk
2. Navigate to the Service Desk > People > Agents
3. Click on the bar under "Issues in progress" for the renamed agent

Expected Results

• The link should take you to the issue navigator where the list of unresolved issues assigned to the agent is displayed

Actual Results

• Your're taking to the Issue Navigator, however, jql reports the following error:

  The value '$old-username' does not exist for the field 'assignee'.

  note that $old-username would be the original username or user key of the renamed user

  Notes

• The problem is occurring because the jql query is still referring to the old username, which is no longer being recognized as a user in JIRA, as the name has been changed.
• Issue is not reproducible in Service Desk 3.0.9, seems to be only an issue with JIRA Service Desk 2.5.x and JIRA 6.x