We've come across this a few times before: a student submit a document for a Workshop activity, but nothing is uploaded when their fellow students want to start with the peer-assessment.
We cannot see in the logs that the student (accidentally) deleted the file in the upload process.
The logs below are for the submission date in question and the submission was not edited again (the due-time was 23:55 on 11 May, so the submission was closed after this).
Have anyone else experienced this before? Do you know of any way to restore the submitted file?