diff --git a/wp-content/themes/twentyseventeen/header.php b/wp-content/themes/twentyseventeen/header.php
index 30d7d2a7c2..27148be6d4 100644
--- a/wp-content/themes/twentyseventeen/header.php
+++ b/wp-content/themes/twentyseventeen/header.php
@@ -41,10 +41,14 @@
 	</header><!-- #masthead -->
 
 	<?php
-	// If a regular post or page, and not the front page, show the featured image.
-	if ( has_post_thumbnail() && ( is_single() || ( is_page() && ! twentyseventeen_is_frontpage() ) ) ) :
+
+	/*
+	 * If a regular post or page, and not the front page, show the featured image.
+	 * Using get_queried_object_id() here since the $post global may not be set before a call to the_post().
+	 */
+	if ( ( is_single() || ( is_page() && ! twentyseventeen_is_frontpage() ) ) && has_post_thumbnail( get_queried_object_id() ) ) :
 		echo '<div class="single-featured-image-header">';
-		the_post_thumbnail( 'twentyseventeen-featured-image' );
+		echo get_the_post_thumbnail( get_queried_object_id(), 'twentyseventeen-featured-image' );
 		echo '</div><!-- .single-featured-image-header -->';
 	endif;
 	?>
diff --git a/wp-includes/version.php b/wp-includes/version.php
index b0ca708cbc..68891eb6dc 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-alpha-39623';
+$wp_version = '4.8-alpha-39624';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.