4.2-alpha title-tag bug

Hi there! When there is category of grandchild, flip to the second page title tag display can’t find the page.
functions.php code –

add_theme_support('title-tag');

function vb_pagination( $query=null ) {

  global $wp_query;
  $query = $query ? $query : $wp_query;
  $big = 999999999;

  $paginate = paginate_links( array(
    'base' => str_replace('#038;','',str_replace( $big, '%#%', esc_url( get_pagenum_link( $big ) ) )),
    'type' => 'array',
    'total' => $query->max_num_pages,
    'format' => '?paged=%#%',
    'current' => max( 1, get_query_var('paged') ),
    'prev_text' => __('<i class="fa fa-chevron-left"></i>', LANGUAGE_ZONE),
    'next_text' => __('<i class="fa fa-chevron-right"></i>', LANGUAGE_ZONE)
    )
  );

  if ($query->max_num_pages > 1) :
?>
<ul class="pagination pagination-md">
  <?php
  foreach ( $paginate as $page ) {
    echo '<li>' . $page . '</li>';
  }
  ?>
</ul>
<?php
  endif;
}

body code –

<?php
		if ( get_query_var('paged') ) {
		$paged = get_query_var('paged');
		} else if ( get_query_var('page') ) {
		$paged = get_query_var('page');
		} else {
		$paged = 1;
		}

		$my_args = array(
		'cat' => get_query_var('cat'),
		'posts_per_page' => 1,
		'paged' => $paged
		);
		$the_query = new WP_Query( $my_args );
		if ( $the_query->have_posts() ) : ?>
		<?php

	 ?>
		<?php while($the_query->have_posts()):$the_query->the_post();?>
		<div class="row">
		<div class="col-md-6">
		<?php
		echo get_the_post_thumbnail( $post_id );
		?>
		</div>
		<div class="col-md-6">
			<h1><?php the_title(); ?></h1>

		</div>
		</div>
		<?php
		endwhile;
		endif;
		wp_reset_postdata();
		?>
</article>
	<!-- row start  -->
	<div class="row text-center">
		<?php
		if ( function_exists('vb_pagination') ) {
			vb_pagination( $the_query );
		} ?>
	</div>
	<!-- row end -->