diff --git a/packages/plugin-legacy/src/index.ts b/packages/plugin-legacy/src/index.ts
index b9e3be2a852802..22a87cc04afeb3 100644
--- a/packages/plugin-legacy/src/index.ts
+++ b/packages/plugin-legacy/src/index.ts
@@ -731,6 +731,7 @@ function polyfillsPlugin(
     load(id) {
       if (id === polyfillId) {
         return (
+          modernChunkLegacyGuard +
           [...imports].map((i) => `import ${JSON.stringify(i)};`).join('') +
           (excludeSystemJS ? '' : `import "systemjs/dist/s.min.js";`)
         )