We're thoroughly puzzled. There are two administrators on our site (aside from the hosting partner) and neither of us made any changes to courses in the past 8 months or so. Until a month or so ago a user with a non-editing teacher role could download grade reports from all the courses he is enrolled in with this role.
Today in two courses he got the error 'Sorry, but you need to be a part of a group to see this page' in another could only view users in his group in another 2. For the other 4 courses on the site he could get the grade reports as always. I checked course group settings (Course administration > Edit settings > Groups) and his enrollment - aligned the assigned roles (removing a custom role in course 1 and 2), and added him to a group in course 3 and 4. This resolved the issue for course 2 and 3. I tried removing him from his group in course 1 and 4, still an error. The work-around I found was adding non-editing teacher to 'access all groups' in Course administration > Users > Permissions for the two courses where he couldn't view the grade report. What still puzzles me is that this permission is not given to the non-editing teacher in any other courses, yet he can access the grade report for all enrolled users.
We're running 3.5.8.
Any idea what is causing this or other settings I should check?