Steps to reproduce the problem:
1. Create a course.
2. Assign user as a student in a course. Assign another user as a student in a category. Assign another user as a student globally. (These three should be different accounts to identify the problem).
3. On Add an Activity, Select "Upload a Single File".
4. Enter Assignment name and description, then set "Use Turnitin Submission" to "Yes".
5. Login as a student.
6. Submit a document. Repeat steps 5 and 6 for the three students.
7. Login in as Administrator.
8. Click on the Assignment you just created with Turnitin.

Observed Behavior:
The link states "View 2 submitted assignments". When I clicked on this link, it shows the documents submitted by the students more than what is stated in the link. This means that it doesn't match the real number of submitted Assignments when Turnitin is used.

Expected Behavior:
The link "View 2 submitted assignments" should match the number of documents submitted in Turnitin. So this should show "View 3 submitted assignments".

Primary Analysis:
Only users that are assigned as a students in each course and in a category are recognized. But when user is assigned as a student globally, when these student submits their assignment, moodle doesn't recognize this as a submitted assignment.