Students permissions setting report for courses not showing grade book shows that grades can be shown. But an error occurs when gradebook is requested.
So that is not an issue explaining that gradebook for the student in the paritcular couses where gradebook is not shown. The students role for courses seems not to be different on the courses.
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An additional discovery is that participians in the courses are shown to the student in spite of that the paramenter settings is set in a way that this should not happen. It seems to me that the parameter settings in Moodle is too complicated, allowing too many errors to occur in the configurations management.