diff --git a/src/core/set_available_bundles.js b/src/core/set_available_bundles.js
index <HASH>..<HASH> 100644
--- a/src/core/set_available_bundles.js
+++ b/src/core/set_available_bundles.js
@@ -18,7 +18,8 @@ define([
 
 		if ( main ) {
 			for ( bundle in main ) {
-				if ( main.hasOwnProperty( bundle ) && bundle !== "root" ) {
+				if ( main.hasOwnProperty( bundle ) && bundle !== "root" &&
+							availableBundleMapQueue.indexOf( bundle ) === -1 ) {
 					availableBundleMapQueue.push( bundle );
 				}
 			}
Avoid enqueuing duplicate bundle for bundle lookup processing (simple optimization)