Hello you all, I think that your problem is that you don't wait enough time after you submit the submissions. The thing is that students have a period of time (I think it's 30 minutes) after they post their submission, to edit it or to delete it, in case they want to change something. In my experience, I've noticed that those submissions don't appear anywhere to be assessed in that period (well, in fact those submissions appear if you are the administrator, but the other students can't see it). It can also be something about the cron job, but I think it's more because of what I said earlier.
Try leaving a gap of 30 minutes (at least) between the end of submissions deadline and start of assessments. I know it's annoying when you are trying with experimental workshops, but it's the only way to get it working correctly. I hope this helps you