Fix for error 404 on last page If using custom pagination for custom post type and with different posts_per_page value from settings. Add to functions.php/queries.php

fix-pagination.php

<?php
/**
 * Fix pagination on archive pages
 *
 * @author JC Palmes
 */
function khleomix_remove_page_from_query_string( $query_string ) {
	if ( isset( $query_string['name'] ) == 'page' && isset( $query_string['page'] ) ) {
		unset( $query_string['name'] );
		$query_string['paged'] = $query_string['page'];
	}
	return $query_string;
}
add_filter( 'request', 'khleomix_remove_page_from_query_string' );