Additional Class Notebook-related features and issues within Microsoft Teams for Education
Hi Hart,
Thanks for using Microsoft products and posting in the community, I'm glad to offer help.
According to Getting Started with the OneNote Class Notebook: A Walkthrough for Teachers, we can see that the "Content Library" section is editable for teachers, and it is read-only for students by default.
However, in your case, the students can edit the content in the "Content Library" section, please go to Teams> "Files" tab > click "Open in SharePoint" to open the team site > go to "Site contents" > open "Sites Assets" folder > search for "_content library" > select the "_ C ontent L ibrary"folder > click "Manageaccess" in the details pane > change the permissions of the student to "Can view".
Hope the above suggestion can be helpful, and please feel free to let me know if there is any progress, I'll continue to help you.
Best Regards,
Arck