Yeah… The closest an instructor can get to preventing that is setting the column (or whole gradebook) to manual posting policy…that way, at least, students aren’t getting notifications for EACH comment/annotation. And also hiding the totals until closer to the end of the semester.

It’d be the student’s notification settings/preferences in Canvas (click Account in the global nav menu -> Notifications and see what’s set for the “Grading” option…it’s probably set to notify immediately). Unfortunately it isn’t something instructors can control.