Affects Version/s: 2.0.1, 2.0.2, 2.0.3
Fix Version/s: None
The error is only visible when AJAX is enabled for the grader report and the ajax_callbacks.php has an error in it.
The replace method doesn't assign the result its parent object(message in this case) - it needs to be assigned to a variable like:
message = message.replace(//, args.type);
message = message.replace(//, this.report.users[args.properties.userid]);
In addition, M.gradereport_grader.users is empty, so we need to use the "this" reference.
I've attached a patch file that resolves the problem as shown above.