diff --git a/lib/web/cookies/index.js b/lib/web/cookies/index.js
index c9c1f28ee1f..5f53d56a81e 100644
--- a/lib/web/cookies/index.js
+++ b/lib/web/cookies/index.js
@@ -102,7 +102,7 @@ function setCookie (headers, cookie) {
   const str = stringify(cookie)
 
   if (str) {
-    headers.append('Set-Cookie', stringify(cookie))
+    headers.append('Set-Cookie', str);
   }
 }