1.Login as a teacher
2.Inside a course ,choose settings->user->enrolled users
3.Now for one enrolled user ,delete all its role make it empty,now click on the other enrolled user and try to assign the rule
4.Enrollment window is not synchronized with the role of the user,like for example if the user is just "student" now the enrollment window will not only have disable student button but it might have a disable "non editable teacher" which is wrong