A teacher can view a students assignment by going to that assignment and clicking Edit and Grade beside the students name.

If they do this - intending to download the assignment but grade it later - and the file the student uploaded was a Word document, the assignment continues to show up when the filter of "Awaiting Grading" is used since it has not been graded yet.

However, if the file that was uploaded by the student is a PDF file, the assignment no longer shows as awaiting grading.

In the case of a PDF file, opening the assignment causes a record to be inserted into the assign_grades table with a grade of -1. This then prevents the assignment from displaying at all when the filter "awaiting grading" appears. This means that teachers have no way of seeing the assignments that they need to work on.

To replicate:
1. Create an assignment that has file upload as the submission status. (I also used a scale rather than a grade but not sure if that makes any difference).
2. Log in as a student and go to the assignment. Upload a PDF file as the assignment and save.
3. Log in as a teacher in the same group as the student. Go to the assignment. Find the student and click Edit then click Grade. Download the file.
4. Go back to the assignment (as the teacher) and choose the filter "Awaiting Grading" to only view assignments that are awaiting grading. The assignment for the student is no longer showing.

Do the same with a Word document as the file being uploaded and the assignment continues to show as outstanding since it has not yet been graded.

What I expected to happen was that the assignment would continue to show as awaiting grading until the teacher actually adds a grade, rather than disappearing when they open it but only if it is a PDF file.