I´m not really shure... but it seems to me that the teachers who are enrolled in the course before you create the assignment show up in alfabetic order (christian name). If you enroll a teacher after the assignment i created he/she will show up on first place. There is no setting available to change the sorting - not even in the admin settings (a hack is there for shure)
Good news - Looks like this is fixed now - I have done a quick check and markers now appear alphabetically.
Thanks
Jim