Can not remove deleted groups/Project Roles from role on people session of a project

Summary

In new menu People available on the project settings of some instances, it is not possible to remove a group of a role if the group was already deleted on user management. Reproducible on JIRA v1000.1210.0

Environment

Steps to Reproduce

1. Click in Cog Icon > User Management
2. On the left panel, click on "Groups"
3. Click to Create a new group (e.g. HR-Admin)
4. navigate to a Project > Project Settings > People
5. Add the Group to any role
6. Navigate back to User Management > Groups and delete the group HR_Admin
7. Wait for 10 minutes
8. Navigate back to Project > Project Settings > People and try to remove the group from the role you added before

P.S: This same problem happens with deleted Project Roles.

Expected Results

The group should be removed from the Role

Actual Results

It is returned the error below and the role is not removed:

Group 'HR-Admin' was not found in the system.

 Workaround

Recreate the group and remove the group from the role. then, delete the group again.