Post Duplicado

Eu coloquei para randomizar meus posts do portfólio com essa linha de código “<?php query_posts(‘&orderby=rand&post_type=portfolio&posts_per_page=’ . $portfolio_post_per_page_query ); ?>” só estou enfrentando problemas com a duplicidade de conteúdos que o a randomização gera na páginação, alguém sabe o que pode ser?

Esse é o código completo da página

<?php get_header() ?>

<?php
if ( function_exists( 'ot_get_option' ) ) {
$portfolio_post_per_page_query = ot_get_option( 'portfolio_post_per_page', '10' );
} else {
$portfolio_post_per_page_query  = '10';
}
?>
<?php query_posts('&orderby=rand&post_type=portfolio&posts_per_page=' . $portfolio_post_per_page_query ); ?>

<!-- Begin .top-filter-bar-container -->
<div class="top-filter-bar-container">
<div class="top-filter-bar border-box-star">
<ul>
<li class="selected-tinyNav"><a class="top-filter-bar-selected" href="#" data-filter=".item">Todas Acompanhantes</a></li>
<?php
$args = array(
'type' => 'portfolio',
'taxonomy' => 'portfolio-category',
);
$filterBarTerms = get_categories( $args );
foreach ($filterBarTerms as $term) {
echo '<li><a href="#" data-filter=".' . $term->slug . '" >'.$term->name.'</a></li>';
}
?>
</ul>
</div>
<!-- End .top-filter-bar-container -->
</div>

<!-- Begin .items-container-wrap -->
<section class="items-container-wrap">
<div class="items-container">
<div class="items-container-responsive">
<?php if (have_posts()) : while (have_posts()) : the_post(); ?>
<?php
$comma_separated = array();
$postTerms = wp_get_post_terms( $post->ID, 'portfolio-category');
foreach ($postTerms as $term) { array_push($comma_separated, $term->slug); }
$comma_separated = implode(" ", $comma_separated);
?>
<div id="portfolio-<?php the_ID(); ?>" <?php post_class('folio-item item ' . $comma_separated ); ?>>
<?php if ( has_post_thumbnail()) : ?>
<?php the_post_thumbnail('portfolio-thumb'); ?>
<?php endif; ?>
<div class="folio-item-hover animate-opacity">
<div class="folio-item-info-container border-box">
<h2 class="folio-item-title"><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>
<h4 class="folio-item-cat"><?php echo get_the_term_list( $post->ID, 'portfolio-category', '', ', ', '' ); ?></h4>
</div>
</div>
<?php
$fullSizeImageSrc = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'full' );
$fullSizeImageSrc = $fullSizeImageSrc['0'];
?>
<?php
$fVideo = trim(get_post_meta( $post->ID, 'folio_video_url', true ));
if ($fVideo === "") {
?>
<a class="folio-item-view animate-folio-hover" rel="prettyPhoto[portfolio-gallery]" href="<?php echo $fullSizeImageSrc; ?>"><div class="folio-item-view"></div></a>
<a class="folio-item-link animate-folio-hover" href="<?php the_permalink(); ?>"><div class="folio-item-link"></div></a>
<?php
} else {
?>
<a class="folio-item-play animate-folio-hover" rel="prettyPhoto[portfolio-gallery]" href="<?php echo $fVideo; ?>"><div class="folio-item-play"></div></a>
<a class="folio-item-link animate-folio-hover" href="<?php the_permalink(); ?>"><div class="folio-item-link"></div></a>
<?php
}
?>
</div>
<?php endwhile; ?>

<!--Begin .page-navigation -->
<!-- Using Ajax so we don't need it -->
<div class="page-navigation">
<?php
global $wp_query;
$number = 999999999;
echo paginate_links( array(
'base' => str_replace( $number, '%#%', get_pagenum_link( $number ) ),
'format' => '?paged=%#%',
'current' => max( 1, get_query_var('paged') ),
'total' => $wp_query->max_num_pages,
'prev_text' => __('Prev Page', 'spnoy'),
'next_text' => __('Next Page', 'spnoy')
) ); ?>
<!--End .page-navigation -->
</div>

<?php endif; ?>
<?php wp_reset_query(); ?>
</div>
</div>
<!-- End .items-container-wrap -->
</section>

<?php get_footer(); ?>