I'm a bit confused about where user grades are actually stored. For the assign module, are they stored in grade_grades and in assign_grades?
I ask because I recently upgraded from 1.9 to 2.5 and noticed that a few things are no longer working. I created a page that does manual grading on assignments and inserts the grade into grade_grades using direct sql (I know, bad idea). It worked fine in 1.9 but no longer in 2.5. Now the grade shows up in the gradebook but does not show up when browsing the submissions for the assignment. My guess is that the grade is in grade_grades but not in assign_grades.
I hope that is clear.