Grader report: Unable to sort using custom profile fields

The Grader reports are not sorted based on the custom profile fields.

Steps:

Pre-requisite:

• Login as Admin to the website.
• Navigate to Site administration
• Go to Users > Accounts > User profile fields.
• Click on 'Create a new profile field' and select Text input. Enter Short name, Name (e.g., Mail ID), set Character limit to 30(or can be up to 255 characters) and Save changes.
• Now go to Site administration > Users > Permissions > User policies. Verify that the newly created profile field is displayed in the 'Show user identity' list.
• Select that field and Save changes. Now this field will be displayed in the Grader report.

To test sorting using this field, we need to update the user's profiles.

• Go to a course with some Grader report data.
• Edit the user profiles to add some text to this new user profile field and save changes (This field will be displayed under 'Other fields' section in the profile) 
• Now in Grader report, click on this field to sort. 

Actual result: Verify that the report is not sorted based on this field.
Expected result: User should be able to sort with the custom profile fields.