D-2 visa Korea D-2 part-time job international student attendance Korea student visa instability Korea international student administrative risk Korea study in Korea student work permit Korea international student job rules korea d-10 visa korea job seeking visa korea student visa korea rules international student korea immigration attendance korea international student visa korea problems international student visa rejection Korea student visa Korea student visa after graduation international student immigration review Korea student visa transfer Korea university change immigration Korea student visa pattern issues Korea part-time work Korea hikorea d10 student part time work korea visa student visa attendance rules Korea student visa korea attendance work rules international student korea immigration international student Korea student visa document mistake Korea student visa korea attendance rules Korean university visa part-time work Korea international students D-4 work permission student attendance Korea