Clicking Save after grading an assignment associated with the GB doesn't return user to the submission overview list if that student hasn't made an actual submission.
1) create an assignment and choose to associate it with an existing GB
2) As instructor, click grade to grade assignment. Choose student name
3) Enter in comments & grade, click Save
--> The page refreshes and the status text states that you are re-grading. The information is saved (you can check GB or reset tool to see this). The user should be returned to the assignment submission listing. I'm marking this as a blocker since the work flow is extremely disrupted. Instructors/graders that encounter this error are likely going to need to call support.