Scenario: Earlier in the semester, an instructor created a group set for an assignment and added five groups. Students were dispersed among those groups at that time. Since that time several students have withdrawn from the course. These students have remained as group members, even though they have been withdrawn from the course. If a student withdraws from a course, the student should also be removed from the group, at least that makes sense to me. So I contacted Canvas support.
Canvas Support's Response: "When a group is created within a course it also creates an entirely separate page or group area for these students within the groups. This area has its own set of people for the course, its own “enrollments” if you will. When they withdraw from the course their enrollment in the course is removed, but the status in the group is retained. You can go under the page for the group and remove the student from the people page if they should no longer appear there. But in short, group pages are kind of like a course in that they have their own set of enrollments and access levels. Users will need to removed from group pages."
My opinion: Groups created from an enrollment within a course should always reflect that course's enrollment. It is a pain for instructors to have to manually remove students from course project groups, especially in large classes. We have a policy that once a student is withdrawn, they should no longer have access to any future course assignments, materials, etc. If the student remains in the group and new content is added to the group space for new assignments, then the student would have access to materials after they have withdrawn from a course. This is an issue for us. We have several courses that create group spaces to work on projects for the duration of the semester.