posts_per_page not working

Hi all,

I turning around since few days now, and i really do not undertand.
I want to limit the number of post i displaying, but it seem not working at all.

My Query :

$mesautresposts = new WP_Query(
array(
	'post_type' => 'post',
	'posts_per_page'=> 10,
	'order' => 'DESC',
	'orderby' => 'date',
	'post__not_in' => $do_not_duplicate,
	'category__not_in' => $category_id,
	'tax_query' => array(
      array(
        'taxonomy' => 'post_format',
        'field' => 'slug',
        'terms' => array( 'post-format-aside, post-format-video' ),
        'operator' => 'NOT IN'
	      )
    ),
	)
);
if($mesautresposts->have_posts()): var_dump($mesautresposts->request);
echo '<p>Number of post :'.$mesautresposts->found_posts.'</p>';

while($mesautresposts->have_posts()): $mesautresposts->the_post(); $do_not_duplicate[] = $post->ID; ?>

<p><?php the_title(); ?></p>

<?php endwhile; endif; wp_reset_postdata(); ?>

When i displaying the SQL query using ‘var_dump($mesautresposts->request);’ i have :

SELECT SQL_CALC_FOUND_ROWS wp_2_posts.ID FROM wp_2_posts WHERE 1=1 AND wp_2_posts.ID NOT IN (5256,5262,5181,5119,5179,5124,4328,4316,4296,4287,5538,5159,5171,5156,4984) AND ( wp_2_posts.ID NOT IN ( SELECT object_id FROM wp_2_term_relationships WHERE term_taxonomy_id IN (193) ) ) AND wp_2_posts.post_type = 'post' AND (wp_2_posts.post_status = 'publish' OR wp_2_posts.post_status = 'private') AND ( wp_2_posts.ID NOT IN ( SELECT object_id FROM wp_2_term_relationships WHERE term_taxonomy_id IN (193) ) ) GROUP BY wp_2_posts.ID ORDER BY wp_2_posts.post_date DESC LIMIT 0, 10

When i testing it directly in the database, all the results are ok, but when i displaying it in the page, it’s not limiting the number of results.

Rather than having 10 post displayed, i have 22 posts displayed, and the found_posts is displaying 132 Posts !

I have look for filters and the pre_get_posts function in y template, and function.php, but nothing seem to modify the query.

Any idea from where it can come from ?