On the assignment view, the students see a green check mark that states graded, but they should be able to see the grade that was given and the comments. If the students receives a 0, it still shows graded and the student doesn't know that they still need to address the assignment.
teachers can control whether students see grades, comments or both (from their gradebook settings). I show this test assignment where I haven't graded Tina but entered a comment and she can see it because I have that setting turned on. I could also have entered a 0 in there as the grade.