conflict with shortcode query

I’ve just updates to 2.0.33 and nextgen has stopped working (just shows the shortcode). I have tracked the problem to a conflict with a shortcode I have in the functions.php file which display posts at the end of a page.I can get nextgen functioning again by deleting the the_content(); line from the following code

/**
 * Add a QUotes Shortcode
 * allows selection of quotes by tag
 */
function im_quotes($atts, $content = null) {
        extract(shortcode_atts(array(
                "num" => '5',
				"tag" => ''
        ), $atts));
        global $post;

		$tmp_post = $post;
		$quotes_args = array(
			'orderby' => 'rand',
			'order' => 'DESC',
			'posts_per_page' => $num,
			'no_found_rows' => true,
			'post_status' => 'publish',
			'post__not_in' => get_option( 'sticky_posts' ),
			'tag' => $tag,
			'tax_query' => array(
				array(
					'taxonomy' => 'post_format',
					'terms' => array( 'post-format-quote' ),
					'field' => 'slug',
					'operator' => 'IN',
				),
			),
		);
		$quotes = get_posts( $quotes_args );
		ob_start();
		echo '<div class="quote-short">';
		echo '
<ul>';
		foreach($quotes as $post) :
	                setup_postdata($post);
				echo '
<li><div class="quote-text">';
				the_content();
				echo '</div><div class="quote-uthor">';
				the_title();
				echo '</div></li>
';
	    endforeach;
		echo '</ul>
';
		echo '</div>';
		$outx = ob_get_contents();;
		$post = $tmp_post;
		ob_end_clean();
        return $outx;
}
add_shortcode("imquote", "im_quotes");

I am struggleing to see why this would cause a problem now – any ideas?

https://www.ads-software.com/plugins/nextgen-gallery/

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