Warning message displays when a student has answered a Mandatory question incorrectly

I have updated to version 1.2.5.1 and have changed the settings for my Questions to be 'Mandatory' I had previously set them to be 'Assessable' as the was an issue where the student had to get all the questions correct before moving to the next unit.

Now that I have my questions set to Mandatory when the student attempts the question and selects an incorrect option when they revisit the page a 'Warning/error message displays.

This is occurring for 'Single Answer' questions. I have created 4 possible answers and the warning message displays 3 times (one for each of the incorrect options)

The Warning message is:

Warning: Missing argument 4 for Student::add_mandatory_questions_meta() in /home/peacefu0/public_html/pponline/wp-content/plugins/coursepress/includes/classes/class.student.php on line 774

Can you please advise me what to do. I have tested this for existing students and new enrolled students

Thanks
Tony