This feedback is linked to the test https://tracker.moodle.org/browse/MDLQA-16700

To reproduce, we must :
1. Login as admin.
2. Go to "Site administration | Grades | General settings" and make sure the "Recover grades default" is unchecked.
3. Create a course with an assignment.
4. Go to the Participants page and enrol one user1
5. Go to the assignment's grading table and enable quick grading.
6. Give grades to user1
7. Unenrol the user1 from the course.
8. Enrol again the user1. During the enrolment click over the "Show more" link and confirm that "Recover user's old grades if possible" is unchecked

In this case, the grade will no longer appear in the gradebook but will appear again in the assignment (see screenshot)

It seems to me that the way it works is confusing and leads to misunderstandings by trainers when a student is manually unenrol from a course and then re-registered with the "do not retrieve grades" option.

I imagine feedback from trainers who sometimes don't manage enrollments, ask themselves (and us !) the following question:
"Why while the grade appears in the assignment activity, it doesn't appear in the gradebook." If the trainer has not managed the enrollment, he believes there is a bug.

It seems to me that the note should be removed from the notebook and the assignment to avoid any misunderstanding by the instructors and a gap between the assignment activity and the gradebook.