Hello - @aylouie - would you please expand on what is meant by 'hidden'? I sense you are using a Canvas feature such as Hide Grades but there is also Grade Posting Policy.
I just read over the following guide, and it states:
When assignment grades are hidden, students will not receive grade change or instructor comment notifications for the assignment. Students will also be unable to view their grades, including grade and score changes, instructor submission comments, Canvas DocViewer comments, and curved grades for the assignment. Students can still see and submit the assignment and will be informed on the student grades page that assignment grades are hidden.
... If you make changes to an assignment with hidden grades, the total score as you see it (in both the Gradebook and the student Grades page) will be affected. However, students will not see any changes when they view their Grades page. Once you post the assignment grades, the total grade in the student's view will update accordingly.
As I read it, students should not be seeing course score changes due to grades being assigned to hidden assignment grades.
But it sounds like you are seeing different behavior. If that is accurate then perhaps a support ticket is in order.
How do I hide or post assignment grades in SpeedGr... - Instructure Community - 1000