I have synced Flipgrid and Canvas and have several assignments that students turned in using Flipgrid.  I am trying to attach rubrics to these assignments in Canvas, but, no matter how many times I try refreshing, etc., I can't seem to find the "+Rubric" button for these assignments as indicated in the Instructor guide.  I haven't had any problems adding rubrics to graded discussions, just these Flipgrid submissions.  Any suggestions for further troubleshooting?