By now, any of us attempting to use an external tool with a rubric have figured out the hacks to get around the glitch. (I first need to create the assignment without the external tool, then add the rubric, then go back and edit the assignment to add the external tool.) However, if I make a mistake when using these hacks or decide after-the-fact to add a rubric for easier grading in speedgrader, it is very difficult to fix it without messing with the students' access to the assignment they're working on, or have already completed.
CANVAS, WHY HAVEN'T YOU FIXED THIS YET? I can find posts going back 8 years about this! PLEASE FIX!