diff --git a/lib/util.js b/lib/util.js
index a00ab7dc..c060fe90 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -912,7 +912,7 @@
                         else
                             all[num] = args[0];
                     
-                    if (!callbackWas && error || isLast) {
+                    if (!callbackWas && (error || isLast)) {
                         callbackWas = true;
                         
                         if (type === 'array')