Hi @martindeal Just to add to what @Bobby2 wrote, is the assignment you have assigned being run through Turnitin with the Canvas integration? We have that integration set up in our system and when I go back to a linked assignment I do not see the regular Speedgrader interface but something like below:
When I went to Speedgrader, it showed me only a test student submission that I don't remember making in class but may have (the course was a while ago), but it was in the Speedgrader window and not the assignment overview page that you posted above. I went to the Grades tab of the class and had a section for test students (again don't remember making this in the course) but was able to change this back to viewing all sections. When I went to the assignment column for the TII assignment and went to SpeedGrader, I see an interface like this:
The submission is not the TII report but if I click the 1% button it opens up another window and shows the TII interface.
Not sure if any of this helps but thought I would add the information in case it does!