Duplicate assignment activity retains original name in gradebook despite being modified in course.

I have created a course carrying a number of assignment activities. In the interest of speed I completed the first activity then created a number of duplicates, each of which I renamed using the 'black pen' edit icon. The first few were duplicates of the original but then later are duplicates of other duplicates as I worked down the page.

If I view the gradebook now I can see all of the assignment activities but they all have the same name as the original making it impossible to tell which grade is for which assignment.