diff --git a/src/Form/ConfigPatchSettings.php b/src/Form/ConfigPatchSettings.php
index 5846b072830668edaa058f68a3fdb741bdb68dd0..7462f06c175f5be32c4f13ca68d4341471ddc07b 100644
--- a/src/Form/ConfigPatchSettings.php
+++ b/src/Form/ConfigPatchSettings.php
@@ -117,8 +117,10 @@ class ConfigPatchSettings extends ConfigFormBase {
     ];
     $config = $this->config('config_patch.settings');
     foreach ($config_fields as $config_field) {
-      $config->set($config_field, $config_values[$config_field])
-        ->save();
+      if (isset($config_values[$config_field])) {
+        $config->set($config_field, $config_values[$config_field])
+          ->save();
+      }
     }
     parent::submitForm($form, $form_state);
   }