diff --git a/code/Model/SiteTree.php b/code/Model/SiteTree.php
index e096acef..511bf4ae 100755
--- a/code/Model/SiteTree.php
+++ b/code/Model/SiteTree.php
@@ -741,13 +741,15 @@ class SiteTree extends DataObject implements PermissionProvider, i18nEntityProvi
     /**
      * Generates a link to edit this page in the CMS.
      *
+     * Implemented here to satisfy the CMSPreviewable interface, but data is intended to be loaded via Extension
+     *
+     * @see SilverStripe\Admin\CMSEditLinkExtension
+     *
      * @return string
      */
     public function CMSEditLink()
     {
-        // This method has to be implemented here to satisfy the CMSPreviewable interface.
-        // See the actual implementation in CMSEditLinkExtension.
-        return $this->extend('CMSEditLink')[0];
+        return $this->extend('CMSEditLink')[0] ?? '';
     }
 
     /**
diff --git a/composer.json b/composer.json
index 278ea854..c18a7a9e 100644
--- a/composer.json
+++ b/composer.json
@@ -45,11 +45,14 @@
     },
     "autoload": {
         "psr-4": {
-            "SilverStripe\\CMS\\": ["code/", "_legacy/"],
+            "SilverStripe\\CMS\\": [
+                "code/",
+                "_legacy/"
+            ],
             "SilverStripe\\CMS\\Tests\\": "code/php/",
             "SilverStripe\\CMS\\Tests\\Behaviour\\": "tests/behat/src/"
         }
     },
     "prefer-stable": true,
     "minimum-stability": "dev"
-}
+}
\ No newline at end of file