diff --git a/lib/cartodb/backends/template_maps.js b/lib/cartodb/backends/template_maps.js
index 907e1c83..e50f078b 100644
--- a/lib/cartodb/backends/template_maps.js
+++ b/lib/cartodb/backends/template_maps.js
@@ -70,13 +70,22 @@ TemplateMaps.prototype._userTemplateLimit = function() {
  */
 TemplateMaps.prototype._redisCmd = function(redisFunc, redisArgs, callback) {
     this.redis_pool.acquire(this.db_signatures, (err, redisClient) => {
-        assert.ifError(err);
+        if (err) {
+            return callback(err);
+        }
+
         redisArgs.push((err, data) => {
+            if (err) {
+                return callback(err);
+            }
+
             if ( ! _.isUndefined(redisClient) ) {
                 this.redis_pool.release(this.db_signatures, redisClient);
             }
-            callback(err, data);
+
+            callback(null, data);
         });
+
         redisClient[redisFunc.toUpperCase()].apply(redisClient, redisArgs);
     });
 };