Students are clicking on their papers to download them but are not clicking on the Feedback button to view comments provided in Crocodoc. This is a serious user interface flaw in that students are missing very important information from their instructors to inform learning and progress on future works.
One solution would be to add a status icon indicating when feedback has been provided via Crocodoc and both when it has and has not been viewed by the student. This would inform students and instructors alike regarding use of this wonder feature in Canvas. (See image.)