Hi @Ladi_Ke,

It sounds like your school may be doing something a bit outside of the "norm" in terms of teacher and student enrollment.  In general, students and teachers should all be enrolled in the same section(s), so that when a cross-listing is done, the teacher no longer would have access to the child course shell anymore, reducing this confusion.  It sounds like your school/institution may have a section for students and then one for teachers...  This can be helpful to make sure the teachers don't lose access to content when cross-listing, but I'm not sure if the benefits outweigh some of the challenges this approach to enrollments gives (like the one you're describing, where teachers are confused about the multiple course shells they still see compared to the students).  If you're an admin, I'd recommend considering a different approach to your enrollment process.  if you're a teacher, I'd recommend talking to your school's Canvas admins about their approach to see if they'd be open to reconsidering it.

If the specific scenario you currently have...  I think students should be added to one of the sections that are now in the parent course, and content only needs to be added to the parent course.

Hope this helps a bit!

-Chris