diff --git a/lib/api/middlewares/pubsub-metrics.js b/lib/api/middlewares/pubsub-metrics.js
index e12708b5..c397dc2f 100644
--- a/lib/api/middlewares/pubsub-metrics.js
+++ b/lib/api/middlewares/pubsub-metrics.js
@@ -25,7 +25,7 @@ function getEventData (req, res) {
     const eventGroupId = normalizedField(req.get('Carto-Event-Group-Id'));
 
     if (!event || !eventSource) {
-        return [undefined, undefined];
+        return { event: undefined, attributes: undefined };
     }
 
     const attributes = {