diff --git a/lib/utils/scope-subtree.js b/lib/utils/scope-subtree.js
index 1ec29e5bcf..7932d27f81 100644
--- a/lib/utils/scope-subtree.js
+++ b/lib/utils/scope-subtree.js
@@ -41,8 +41,8 @@ export function scopeSubtree(container, shouldObserve = false) {
 
   const scopify = (node) => {
     // NOTE: native qSA does not honor scoped DOM, but it is faster, and the same behavior as Polymer v1
-    const descendants = ShadyDOM['nativeMethods']['querySelectorAll'].call(node, '*');
-    const elements = [node, ...descendants];
+    const elements = Array.from(ShadyDOM['nativeMethods']['querySelectorAll'].call(node, '*'));
+    elements.push(node);
     for (let i = 0; i < elements.length; i++) {
       const el = elements[i];
       const currentScope = ScopingShim['currentScopeForNode'](el);