Index: src/wp-includes/class-wp.php
===================================================================
--- src/wp-includes/class-wp.php	(revision 49808)
+++ src/wp-includes/class-wp.php	(working copy)
@@ -597,8 +597,8 @@
 			$GLOBALS['single'] = 1;
 		}
 
-		if ( $wp_query->is_author() && isset( $wp_query->post ) ) {
-			$GLOBALS['authordata'] = get_userdata( $wp_query->post->post_author );
+		if ( $wp_query->is_author() ) {
+			$GLOBALS['authordata'] = get_userdata( get_queried_object_id() );
 		}
 	}
 
Index: tests/phpunit/tests/general/template.php
===================================================================
--- tests/phpunit/tests/general/template.php	(revision 49808)
+++ tests/phpunit/tests/general/template.php	(working copy)
@@ -589,4 +589,37 @@
 			array( 0, false ),
 		);
 	}
+
+	/**
+	 * @ticket 44183
+	 */
+	function test_get_the_archive_title_is_correct_for_author_queries() {
+		$user_with_posts = $this->factory()->user->create_and_get(
+			array(
+				'role' => 'author',
+			)
+		);
+		$user_with_no_posts = $this->factory()->user->create_and_get(
+			array(
+				'role' => 'author',
+			)
+		);
+
+		$this->factory()->post->create( [
+			'post_author' => $user_with_posts->ID,
+		] );
+
+		// Simplify the assertion by removing the default archive title prefix:
+		add_filter( 'get_the_archive_title_prefix', '__return_empty_string' );
+
+		$this->go_to( get_author_posts_url( $user_with_posts->ID ) );
+		$title_when_posts = get_the_archive_title();
+
+		$this->go_to( get_author_posts_url( $user_with_no_posts->ID ) );
+		$title_when_no_posts = get_the_archive_title();
+
+		// Ensure the title is correct both when the user has posts and when they dont:
+		$this->assertSame( $user_with_posts->display_name, $title_when_posts );
+		$this->assertSame( $user_with_no_posts->display_name, $title_when_no_posts );
+	}
 }