When an enrolment method is disabled, participants who had been enrolled with this method lose access to the course.

This may be a design choice and not a bug, given that the user does not see the course listed on the Course Overview block anymore.

But there is an inconsistency when the Grades page is visited. The course appears on this page, and clicking on it leads to a page saying he's not enrolled in the course (and it was listed under "Courses I am taking" on the previous page).

To reproduce: Create a new course and add a student manually. Proceed to disable the manual enrolment method. Visiting the Grades overview from this student's account will reproduce the problem. This also causes the same problem in the mobile application.