Hi, can you try this out in the beta environment and see if you are still able to reproduce the same behavior? The Gradebook team has some new functionality available in the beta environment (to be in production November 18), and they've also been working on fixing performance issues.
If you're still able to reproduce in the beta environment, we'll need some additional information from you to help triage what you're seeing by submitting a support case.
I just got off the phone with one of our instructors and the new gradebook is not showing his period 3 section is now gone and only the Test Student shows for that section. As an admin I can see his period 3 students but he can not and when I did an "act as user" to masquerade as the teacher I was also unable to see section 3 students in the gradebook.
Here is the link to the course https://hbuhsd.instructure.com/courses/32814/settings
I've disabled the new gradebook and then it does show section 3... feel free to enable it if needed to test this bug.
I'm sorry you're still experiencing this behavior. Unfortunately I'll need you to submit a case to Canvas support. Sounds like it may be a small issue related to permissions, but Canvas support can triage for sure and let our engineers know.