Issue Summary

On a Private Team-managed project, only users with access can be added as an assignee to the issues; however, in the List view assignee quick filter, all site users are shown, including external JSM users.

This is reproducible on Data Center: (no)

Steps to Reproduce

1. Create a Business TMP.
2. Add users to Access groups
3. Set the Project as Private.
4. Go to the List View > Select Quick Filter > More Filters > Assignee
5. A list of all users on the site will be shown

Expected Results

Only users with project access should be shown

Actual Results

• Access:
  
• Filter
  

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available.