You can grade and provide feedback on graded discussion submissions and graded group discussion submissions in SpeedGrader. Discussion posts and replies will display individually, but the replies can also be viewed in the context of the full discussion in SpeedGrader.

You can access the SpeedGrader either from vertical ellipsis options icon within the Discussion or from the Grades for that specific graded discussion item. 

You will not be notified in the Gradebook of additional posts to discussions after a grade has been entered.