Users enrolled in a Canvas course who have a change of enrollment (ie Guest Student to Auditor, Visitor to Student) may be removed from their groups in Canvas.
This is most commonly seen when person's status in the course changes from Visitor to Student during registration and the add / drop period.
Workarounds
- Allow for joinable groups during visitor period. This will let students re-join the group after they discover they have been removed.
- Avoid using Canvas Groups when the course roster is still being finalized.
More information about setting up Groups can be found here: