diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 97f9903..12d27e7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -22,7 +22,7 @@ jobs:
         run: echo "::set-output name=dir::$(yarn config get cacheFolder)"
 
       - name: Restore yarn cache
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         id: yarn-cache # use this to check for `cache-hit` (`steps.yarn-cache.outputs.cache-hit != 'true'`)
         with:
           path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
diff --git a/src/styleSheetSerializer.js b/src/styleSheetSerializer.js
index 3714bfb..aa0748d 100644
--- a/src/styleSheetSerializer.js
+++ b/src/styleSheetSerializer.js
@@ -2,13 +2,19 @@ const css = require('@adobe/css-tools');
 const { getCSS, getHashes } = require('./utils');
 
 let cache = new WeakSet();
+
 const getNodes = (node, nodes = []) => {
-  if (typeof node === 'object') {
-    nodes.push(node);
+  if (!node || typeof node !== 'object') {
+    return nodes;
   }
 
-  if (node.children) {
-    Array.from(node.children).forEach((child) => getNodes(child, nodes));
+  nodes.push(node);
+
+  if (node.children && typeof node.children === 'object') {
+    try {
+      Array.from(node.children).forEach((child) => getNodes(child, nodes));
+    } catch (_) {
+    }
   }
 
   return nodes;