Canvas doesn't have a default role named Grader, @KMorganPhd, so I assume that your institution's Grader role is based on the TA role and used that role for my testing. I see that TAs do have a to do list showing the ungraded assignment submissions in their courses. I wonder what role your graders have been assigned in Canvas. You can check this by viewing the People page in your course.
Please reply and share if this helps. Those of our colleagues who have experienced something similar can benefit from your question.
