If you're To Do List in Google Classroom is being glitchy, the Google Classroom app probably needs updating.
Delete the app by holding your finger down on the app until the X or "delete" pops up on the screen
Go to Self Service, find the app again and Reinstall
** This is a great tip for any app found in Self Service that is internet-based such as any Google apps, Safari, Chrome (work will never be lost with internet-based apps if you delete the app or switch devices)