Do you plan to edit grades manually in the gradebook (override), and then run the SQL code to remove the grades that you just gave?
Interestingly, although currently not 'overridden' (ie not orange) the grades are not showing in the assignment page (and thus the user activity report) - but do show in the user report from the grader report page.
If you have not provided grades via the assignment, then they are non-existing.
Your students will not see anything in the assignment and in the gradebook.
May be I am not understanding the issue though
Do you mean that you gave a grade via assignment tool, but the grades fails to show there?
All a bit confusing - especially for the students. It also means we have to manually change the grades in the assignment to re-award them and make them appear ie change all of them rather than just the ones that need changing.
I would recommend to use assignment to provide grades, and gradebook to import grades for manually created column ts, or quick manual fixes.
sometimes you want the bigger assignment grading box say for an initial comment, then later just need to edit bits of that comment as the work changes when quick feedback works better - or vice versa
Take a look at the Feedback area of the the grade columns (click edit icon). This is where you can also make minor tweaks to the comments provided via the assignment originally. Once changed it will show up in both places.