diff --git a/system/src/Grav/Common/Page/Page.php b/system/src/Grav/Common/Page/Page.php
index 199660852..ea10cd47b 100644
--- a/system/src/Grav/Common/Page/Page.php
+++ b/system/src/Grav/Common/Page/Page.php
@@ -1696,7 +1696,7 @@ class Page implements PageInterface
             // Get initial metadata for the page
             $metadata = array_merge($metadata, Grav::instance()['config']->get('site.metadata'));
 
-            if (isset($this->header->metadata)) {
+            if (isset($this->header->metadata) && is_array($this->header->metadata)) {
                 // Merge any site.metadata settings in with page metadata
                 $metadata = array_merge($metadata, $this->header->metadata);
             }