wrong results using group_concat

CREATE TABLE `subject` (

  `subject_id` int(6) NOT NULL,

  `name` varchar(50) NOT NULL,

  `course_id` int(6) NOT NULL,

  `teacher_id` int(6) NOT NULL,

  `load_type` varchar(20) NOT NULL,

  `hours` int(11) NOT NULL,

  `area_id` int(2) NOT NULL,

  `active` tinyint(1) NOT NULL,

  `number_exam` int(6) NOT NULL,

  `parent` int(5) NOT NULL,

  `print_visible` tinyint(1) NOT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1;

INSERT INTO `subject` (`subject_id`, `name`, `course_id`, `teacher_id`, `load_type`, `hours`, `area_id`, `active`, `number_exam`, `parent`, `print_visible`) VALUES

(80, 'Lengua y Literatura', 8, 0, '1', 4, 2, 0, 4, 0, 1),

(81, 'Matemática', 8, 0, '1', 4, 2, 0, 4, 0, 1),

(82, 'Ciencias Sociales', 8, 0, '1', 4, 2, 0, 4, 0, 1),

(83, 'Ciencias Naturales', 8, 0, '1', 4, 2, 0, 4, 0, 1),

(84, 'Italiano', 8, 0, '2', 5, 2, 0, 4, 0, 1),

(85, 'Inglés', 8, 0, '2', 4, 2, 0, 4, 0, 1),

(86, 'Expresion Plástica', 8, 0, '2', 3, 2, 0, 2, 0, 1),

(87, 'Música', 8, 0, '2', 2, 2, 0, 2, 0, 1),

(88, 'Informática', 8, 0, '2', 3, 2, 0, 2, 0, 1),

(89, 'Educación Física', 8, 0, '2', 2, 2, 0, 2, 0, 1);

CREATE TABLE `evaluations_mark` (

  `mark_id` int(13) NOT NULL,

  `note` varchar(225) NOT NULL,

  `comments` text NOT NULL,

  `subject_id` int(13) NOT NULL,

  `course_id` int(13) NOT NULL,

  `user_id` int(13) NOT NULL,

  `evaluation_id` int(13) NOT NULL,

  `number_exam` int(2) NOT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1;

INSERT INTO `evaluations_mark` (`mark_id`, `note`, `comments`, `subject_id`, `course_id`, `user_id`, `evaluation_id`, `number_exam`) VALUES

(125, 'SA', '', 80, 8, 28265, 0, 1),

(147, 'MSA', '', 82, 8, 28265, 0, 1),

(169, 'MSA', '', 83, 8, 28265, 0, 1),

(191, 'SA', '', 81, 8, 28265, 0, 1),

(1078, 'SA', '', 85, 8, 28265, 0, 1),

(1430, 'MSA', '', 84, 8, 28265, 0, 1),

(2634, 'MSA', '', 89, 8, 28265, 0, 1),

(3279, 'MSA', '', 83, 8, 28265, 0, 2),

(3510, 'MSA', '', 85, 8, 28265, 0, 2),

(3646, 'MSA', '', 88, 8, 28265, 0, 1),

(3753, 'SA', '', 80, 8, 28265, 0, 2),

(3775, 'SA', '', 81, 8, 28265, 0, 2),

(3797, 'SA', '', 82, 8, 28265, 0, 2),

(4363, 'SA', '', 87, 8, 28265, 0, 1),

(4892, 'MSA', '', 84, 8, 28265, 0, 2),

(6858, 'MSA', '', 86, 8, 28265, 0, 1);

ALTER TABLE `evaluations_mark`

  ADD PRIMARY KEY (`mark_id`);

SELECT subject.name as subject, GROUP_CONCAT(evaluations_mark.note order by subject.name asc) as mark 

FROM evaluations_mark 

LEFT JOIN subject ON evaluations_mark.subject_id = subject.subject_id

WHERE evaluations_mark.number_exam IN (1,2) AND evaluations_mark.user_id = 28265

AND subject.print_visible='1' 

AND subject.number_exam = '4' 

GROUP BY evaluations_mark.subject_id

ORDER by subject.name ASC

subject	            mark

Ciencias Naturales  MSA,MSA

Ciencias Sociales   MSA,MSA

Inglés	            MSA,SA

Italiano	    MSA,MSA

Lengua y Literatura MSA,SA

Matemática	    SA,SA

subject	            mark

Ciencias Naturales  MSA,MSA

Ciencias Sociales   SA,MSA

Inglés	            MSA,SA

Italiano	    MSA,MSA

Lengua y Literatura SA,SA

Matemática	    SA,SA