diff --git a/packages/grafana-prometheus/src/language_provider.ts b/packages/grafana-prometheus/src/language_provider.ts
index c75a21c83de..22c427c979b 100644
--- a/packages/grafana-prometheus/src/language_provider.ts
+++ b/packages/grafana-prometheus/src/language_provider.ts
@@ -251,7 +251,7 @@ export default class PromQlLanguageProvider extends LanguageProvider {
     const res = await this.request(url, [], searchParams, this.getDefaultCacheHeaders());
     if (Array.isArray(res)) {
       this.labelKeys = res.slice().sort();
-      return res.slice().sort();
+      return [...this.labelKeys];
     }
 
     return [];