Custom Post Type Singular Page with Pagination

The Problem

I’m unable to do any sort of pagination (built in or plugin) with a WP_Query on a singular post type page using custom permalinks.

Pagination does work with the default permalink structure.

The Code

Registering the Post Type

/* Arguments for the client post type. */
$client_args = array(
	'labels' => $client_labels,
	'capability_type' => 'page',
	'public' => true,
	'can_export' => true,
	'query_var' => true,
	'rewrite' => array( 'slug' => 'client', 'with_front' => false ),
	'supports' => array( 'title', 'editor', 'excerpt', 'thumbnail', 'custom-fields', "{$prefix}-post-settings", 'entry-views' ),
	'taxonomy' => array( 'category' )
);

register_post_type( apply_filters( 'mba_client_post_type', 'client' ), apply_filters( 'mba_client_post_type_args', $client_args ) );

The Loop

<?php
$slug = basename(get_permalink());
$temp = $wp_query;
$wp_query = null;
$wp_query = new WP_Query();
$args = array( 'posts_per_page' => '-1', 'post_type' => 'press', 'clients' => $slug, 'paged' => $paged );
$wp_query->query($args);
?>
<?php while ( $wp_query->have_posts() ) : $wp_query->the_post(); ?>

<!-- do stuff -->

<?php endwhile; ?>

</div><!-- .gallery -->
<?php previous_posts_link(); ?>
<?php next_posts_link(); ?>
<?php $wp_query = null; $wp_query = $temp; ?>
<?php wp_reset_query(); ?>

Template

My post_type is client so I’m using client.php to show the singular post. The template then pulls in posts from another post type, press. The press posts should pagination.

Desired URLs: https://maxborgesagency.com/client/ibuypower/ and https://maxborgesagency.com/client/ibuypower/page/2/

Currently when you go to https://maxborgesagency.com/client/ibuypower/page/2/ you are redirected back to https://maxborgesagency.com/client/ibuypower/

So those desired URLs don’t work, but these do when the permalink structure is set to default: https://maxborgesagency.com/?client=ibuypower&paged=2

I’m thinking that WordPress just isn’t able to understand the rewritten URL properly.

Any ideas?