When attempting to edit courses under a specific department in Core, users are taken to the Grade Distribution reporting screen instead of expanding the courses.
This is part of the new "SKY" reporting that was recently released. This screen allows you to see the distribution for the department as a whole when clicking on the name of the department itself. These reports can also be filtered down by Year, Grade Plan, and Specific Grades (1st Trimester, Final, etc.) to allow you to view more precise information.
To get to the specific Courses to edit, simply click anywhere else on the Banner other than the Department Name and it will expand it to allow you to edit the courses (shown as any area not highlighted in red.)