diff --git a/core/modules/ckeditor/src/Plugin/Editor/CKEditor.php b/core/modules/ckeditor/src/Plugin/Editor/CKEditor.php
index a6d6fb5647..9058a749ef 100644
--- a/core/modules/ckeditor/src/Plugin/Editor/CKEditor.php
+++ b/core/modules/ckeditor/src/Plugin/Editor/CKEditor.php
@@ -261,7 +261,7 @@ public function getJSSettings(Editor $editor) {
     $enabled_plugins = array_keys($this->ckeditorPluginManager->getEnabledPluginFiles($editor, TRUE));
     foreach ($enabled_plugins as $plugin_id) {
       $plugin = $this->ckeditorPluginManager->createInstance($plugin_id);
-      $settings += $plugin->getConfig($editor);
+      $settings = array_merge($settings, $plugin->getConfig($editor));
     }
 
     // Fall back on English if no matching language code was found.