Steps to Recreate:

1. Create an Assignment which accepts document submissions.
2. Assign students on the assignment to Groups.
3. Submit a document for each Group.
4. Grade the work and set the Workflow State of the grade to 'Released'.
5. Call the mod_assign_get_submissions API endpoint to retrieve the submission details.

What Happens:

The JSON returned from the call includes...

"gradingstatus": "notmarked"

What I Expect To Happen:

The JSON should return the grading status, as set within the Moodle UI, of 'Released'

"gradingstatus": "released"