Currently, when students are un-enrolled from a Canvas course then re-enrolled in the course, much of their student information and data is retained. Unfortunately, their "Group" memberships are not one of those pieces of information. I would sincerely ask that Group membership be recoverable when a student is un-enrolled. Ideally, if a student is un-enrolled, then re-enrolled in the same course, Group membership should come back as seamlessly as the other student information. This could also work if a student is un-enrolled then re-enrolled within a certain time span or if this could be an account-level option.
Here's the case:
The Student Information System (SIS) normally feeds into Canvas and enrolls students. It also un-enrolls students when they drop the course. All seems happy, until:
The Dark Times
The SIS feed has an error, un-enrolling thousands of students. It only takes a couple hours to fix the feed and get the students to most of their data, but vast numbers of students can no longer access their group information. Even worse, the Canvas Account Admin has no way to recover the group membership and can't help fix the problem. Faculty and students alike blame Canvas and/or the Admin, making for a very rough time.
Be kind to the hard-working Admin. Re-enroll students into groups when they re-enroll in a course.