The piece of paper called a ‘diploma’ is one thing; the school records for the student are quite another.
I recall being told that a student is ‘graduated from’ a given school and it is up to that school whether they will confer a diploma or not.
Still, the whole issue here, on first blush at least, seems more than a little silly,
What, pray tell, did the Superintendant actually tell this young lady (who is obviously not guilty of anything ~ ever!)