How to display single post from custom post type loop?

Your single.php is coded in a way that show all posts like archive, it needs to be modified.

To fetch current post, try something like that instead:

<?php get_header(); ?>

<section id="content">
    <div class="wrap-content blog-single">

    <?php  while ( have_posts() ) : the_post(); ?>
        <article id="post-<?php the_ID(); ?>" <?php post_class(); ?>>
            <?php the_title( '<h1>','</h1>' );  ?>
            <div class="post-thumbnail"><?php the_post_thumbnail(array(250, 250)); ?> </div>
            <div class="entry-content"><?php the_content(); ?></div>
        </article>
    <?php endwhile; ?>

    </div>

</section>
<?php get_footer(); ?>