Hi,
I have a service project (cloud) where different support groups can work on issues based on the type of issue. For instance, Business Applications issues are worked by support team "AppSupport". IT technical issues are worked by support team "HelpDesk".
I have groups for these agents and have assigned users to their group. I have a custom field called Support Team that is shown on my issues to denote who owns the ticket and what agents can be assigned to it.
I have set the Assignable Users permission on my project to Admin and "Group custom field value" = Support Team.
I ONLY want the people in the group associated with the Support Team to be able to be assigned this issue. I do not want all Service Desk Team members to be in that list of possible assignees.

This works when I update it. It works great! For awhile and then randomly, the system will revert and put Service Desk Team members and "add-on access" back in that permission. And I can "ignore errors" but then they come back.
What is going on? Do I need to update this somewhere else too? Do I need to do something different? How do I get this to stick?
Any help would be greatly appreciated as this is a critical issue for us. I can't go live without this working.
Thanks!!