Reroll The patch as Per The #2.

Closes #3461951

src/FlagLinkBuilder.php

@@ -52,7 +52,10 @@ class FlagLinkBuilder implements FlagLinkBuilderInterface, TrustedCallbackInterf
     $flag = $this->flagService->getFlagById($flag_id);
 
     $link_type_plugin = $flag->getLinkTypePlugin();
-    return $link_type_plugin->getAsFlagLink($flag, $entity, $view_mode);
+    if ($entity) {
+      return $link_type_plugin->getAsFlagLink($flag, $entity, $view_mode);
+    }
+    return [];
   }
 
 }