Index: src/wp-content/themes/twentynineteen/header.php
===================================================================
--- src/wp-content/themes/twentynineteen/header.php	(revision 43948)
+++ src/wp-content/themes/twentynineteen/header.php	(working copy)
@@ -31,10 +31,17 @@
 
 			<?php if ( is_singular() && twentynineteen_can_show_post_thumbnail() ) : ?>
 				<div class="site-featured-image">
-					<?php twentynineteen_post_thumbnail(); ?>
-					<?php the_post(); ?>
-					<?php $discussion = ! is_page() && twentynineteen_can_show_post_thumbnail() ? twentynineteen_get_discussion_data() : null; ?>
-					<div class="<?php echo ( ! empty( $discussion ) && count( $discussion->responses ) > 0 ) ? 'entry-header has-discussion' : 'entry-header'; ?>">
+					<?php
+						twentynineteen_post_thumbnail();
+						the_post();
+						$discussion = ! is_page() && twentynineteen_can_show_post_thumbnail() ? twentynineteen_get_discussion_data() : null;
+
+						$classes = 'entry-header';
+						if ( ! empty( $discussion ) && absint( $discussion->responses ) > 0 ) {
+							$classes = 'entry-header has-discussion';
+						}
+					?>
+					<div class="<?php echo $classes; ?>">
 						<?php get_template_part( 'template-parts/header/entry', 'header' ); ?>
 					</div><!-- .entry-header -->
 					<?php rewind_posts(); ?>