Trying to remove a preferred role from case form won't let me

I just quickly went in to force the Admin role to a secondary case form to run some tests. When finished, I simply wanted to remove this forced assignment and went into the case and removed it from checklist, saved and then when I looked at the setting, it was checked again. No matter what, I could not remove this.

Workaround:
Create a temporary form, assign the preferred roles to it, save it, then edit it and delete the form.

This removes the checkbox.

-Steve