Selecting or Unselecting the All option from the Custom Fields cog causes the value set in the Read Only Single Select List to reset to None even by users who have limited access

Steps to Reproduce

1. Open the behaviour configuration. In this behaviour I have set the custom field to read only for all users except for the Administrators Group as shown in image_1.png.
2. Next I view the Users under User Management. In this the Mock user is not in the Administrative group. So, I am going to test the behaviour on another browser using this User.
3. I now open another web browser and log into Jira using the Mock user. Once in, I go to the Project and open the issue which was just created.
4. When the issue is open, as expected, the Behaviour List is not editable.
5. Now click Configure Fields cog and select All

Current Behaviour

When the All option is selected the list which is not editable suddenly auto resets to the None option

Expected Behaviour

The value of the Read-Only List must not change when the All fields option is selected

Additional Info

A test video is included for reference.