I am using Moodle 2.3.2 and I am having a problem with students not being able to see their grades once a topic is hidden. Listed are the steps to recreate the problem. I use Topics Format. Problem will manifest itself whether you use Topics or Weekly format.

1. As a teacher, create and assignment.
2. As a student, upload assignment.
3. As a teacher, grade the assignment.
4. As a student, click grades, view grade reporter.
5. Individual assignment grades are visible.
6. As a teacher, go into course, turn editing on, click on the eyeball to hide the entire section.
7. As a student, click grades, view grade reporter.
8. Individual assignment grades are no longer visible.

Students should be able to see their graded assignments and grades even if the topic has been set to hide.

I can repeat the exact same steps in Moodle 1.9.12 and students can see their grades and assignments. Everything works, as it should.

All grade book settings are set at their default values after a fresh installation. I looked in all of the settings and advanced settings areas and nothing appears out of place.