Problema con función wp_is_mobile y count++ en WordPress

<?php
/**
 * The main template file
 *
 * This is the most generic template file in a WordPress theme
 * and one of the two required files for a theme (the other being style.css).
 * It is used to display a page when nothing more specific matches a query.
 * e.g., it puts together the home page when no home.php file exists.
 *
 * Learn more: {@link https://codex.wordpress.org/Template_Hierarchy}
 *
 * @package WordPress
 * @subpackage Twenty_Fifteen
 * @since Twenty Fifteen 1.0
 */

get_header(); ?>

	<div id="primary" class="content-area">
		<main id="main" class="site-main" role="main">

		<?php if ( have_posts() ) : ?>

			<?php if ( is_home() && ! is_front_page() ) : ?>
				<header>
					<h1 class="page-title screen-reader-text"><?php single_post_title(); ?></h1>
				</header>
			<?php endif; ?>

			<?php
			// Start the loop.
				$count = 0;
			while ( have_posts() ) : the_post();

				/*
				 * Include the Post-Format-specific template for the content.
				 * If you want to override this in a child theme, then include a file
				 * called content-___.php (where ___ is the Post Format name) and that will be used instead.
				 */
				get_template_part( 'content', get_post_format() );

if ($count % 3 == 0){ ?>

<!-- hacer algo, por ejemplo, mostrar un anuncio, nota. cita, etc. -->

<?php if (wp_is_mobile()) : ?>
      <!-- CODIGO QUE SE MOSTRARÁ EN MÓVILES/TABLETS -->
	<div align="center"><br>edizzz<script async src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
<!-- adaptable -->
<ins class="adsbygoogle"
     style="display:block"
     data-ad-client="ca-pub-000"
     data-ad-slot="4704642579"
     data-ad-format="auto"></ins>
<script>
(adsbygoogle = window.adsbygoogle || []).push({});
</script></div>
	      <!-- FIN DEL CODIGO QUE SE MOSTRARÁ EN MÓVILES/TABLETS -->

<?php else: ?>
     <!-- CÓDIGO QUE SE MOSTRARÁ EN DESKTOP -->
	 <div align="center"><br><script async src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
<!-- 728 x 90 -->
<ins class="adsbygoogle"
     style="display:inline-block;width:728px;height:90px"
     data-ad-client="ca-pub-000"
     data-ad-slot="3584494738"></ins>
<script>
(adsbygoogle = window.adsbygoogle || []).push({});
</script>
</div>
<!-- FIN CÓDIGO QUE SE MOSTRARÁ EN DESKTOP -->
<?php endif; ?>
<?php
	    }
    $count++;
			// End the loop.
			endwhile;

			// Previous/next page navigation.
			the_posts_pagination( array(
				'prev_text'          => __( 'Previous page', 'twentyfifteen' ),
				'next_text'          => __( 'Next page', 'twentyfifteen' ),
				'before_page_number' => '<span class="meta-nav screen-reader-text">' . __( 'Page', 'twentyfifteen' ) . ' </span>',
			) );

		// If no content, include the "No posts found" template.
		else :
			get_template_part( 'content', 'none' );

		endif;
		?>

		</main><!-- .site-main -->
	</div><!-- .content-area -->

<?php get_footer(); ?>