There was an undocumented change in Canvas's 7/15/26 deploy to the Canvas REST API that changed what section data is reported in courses with cross-listed sections and teachers that are limited from viewing students in other sections. This has resulted in some students being prevented from participating in Harmonize assignments that are set to section visibility. Our team is actively working with Instructure Support on resolving this issue. In the meantime, our product will be rolling out changes to Harmonize to help mitigate it's effects.
If you have a question about a specific course or assignment, we encourage you to use the new Help Menu (look for the large question mark icon at the top of any Harmonize page) or submit a ticket on our help site: https://help.harmonizelearning.com/hc/en-us/requests/new