The assignee picker can show duplicated last user on the list, compounding on multiple clicks of the assignee field.
- Create a Jira instance with 15 or more users
- Create a project with an issue in it, and assign the issue to one of the users
- Change the assignee to another user, and refresh the issue
- Click the assignee field, and scroll down the list
No users are duplicated.
Last user on the list will be duplicated in the list.
There are multiple requests to the <base-url>/rest/api/latest/user/assignable endpoint. The rest endpoint is hit when clicking the "down" arrow, and when scrolling to the bottom of the list.
There is no workaround at this time.