Paging fails when custom template used for home page

I have created a custom page template which I believe would be considered a “showcase” type in that it allows static text, but when viewed, includes a post stream (in all but one excluded category, specified using a custom variable). This template works correctly, including paging of the post stream. However, as soon as I designate the page to be my home page, the paging stops working: I get the 4 most recent posts (plus a sticky one) but when I click on “<– Older posts”, I do see “/page/2” appended to the URL (which is the site URL since this is the home page) but I still get only the same set of recent posts.
Site URL: https://allsaintschelms-new.dreamhosters.com/
Here is the code for the template:

<?php
/*
Template Name: X-Category
*/

/* This example is for a child theme of Twenty Twelve:
*  You'll need to adapt it the HTML structure of your own theme.
*/

get_header(); ?>

	<div id="primary" class="content-area">
		<div id="content" class="site-content" role="main">
        <?php
        /* The loop: the_post retrieves the content
         * of the new Page you created to list the posts,
         * e.g., an intro describing the posts shown listed on this Page..
         */
        if ( have_posts() ) :
            while ( have_posts() ) : the_post();

              // Display content of page
              get_template_part( 'content', get_post_format() );
              wp_reset_postdata();

            endwhile;
        endif;

    $category = get_post_meta( $posts[0]->ID, 'category', true );
    $cat = get_cat_ID( $category );

    $paged = ( get_query_var( 'paged' ) ) ? get_query_var( 'paged' ) : 1;
    $post_per_page = 4; // -1 shows all posts
    $do_not_show_stickies = 0; // 0 to show stickies
    $args=array (
      'category__not_in' => array( $cat ),
      'orderby' => 'date',
      'order' => 'DESC',
      'paged' => $paged,
      'posts_per_page' => $post_per_page,
      'ignore_sticky_posts' => $do_not_show_stickies
    );

    $temp = $wp_query;
    $wp_query = null;
    $wp_query = new WP_Query( $args );
    ?>
    <?php if ( $wp_query->have_posts() ) : ?>

                 <div class="catsec">
			<?php global $more; /* The loop */ ?>
			<?php while ( $wp_query->have_posts() ) : $wp_query->the_post(); ?>
				<?php $more = 0; // Display content of posts ?>
				<?php get_template_part( 'content', get_post_format() ); ?>
			<?php endwhile; ?>

			<?php twentytwelve_content_nav( 'nav-below' ); ?>

		<?php else : ?>
			<?php get_template_part( 'content', 'none' ); ?>
		<?php endif; ?>

                 </div><!-- .catsec -->

		</div><!-- #content -->

    <?php
    $wp_query = null;
    $wp_query = $temp;
    ?>

    </div><!-- #primary -->

<?php get_sidebar(); ?>
<?php get_footer(); ?>