diff --git a/wp-includes/cron.php b/wp-includes/cron.php
index f4810e55a3..41efeebc44 100644
--- a/wp-includes/cron.php
+++ b/wp-includes/cron.php
@@ -118,7 +118,11 @@ function wp_schedule_single_event( $timestamp, $hook, $args = array(), $wp_error
 	 * current time) all events scheduled within the next ten minutes
 	 * are considered duplicates.
 	 */
-	$crons     = (array) _get_cron_array();
+	$crons = _get_cron_array();
+	if ( ! is_array( $crons ) ) {
+		$crons = array();
+	}
+
 	$key       = md5( serialize( $event->args ) );
 	$duplicate = false;
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index a7b986719d..47b53ae64d 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-51915';
+$wp_version = '5.9-alpha-51916';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.