Apple Classroom Sync issues

I am using Apple School Manager and Mosyle as my MDM to manage a shared trolley of iPads between 2 classrooms. All has gone well until I recently amended our classroom roster. 2 new students were added and 1 removed from the roster. All appears as it should be, both in ASM and Mosyle. Each class shows the correct roster. Unfortunately, the Classroom App on my Teacher device does not reflect the amended classroom roster. I've waited a while to see that the device has synced. I've now seen the new classroom roster appear on the shared iPads (the class photos appear for the amended class), I've re-installed the App on the teacher device but it still shows the 'old' class roster... any ideas?