CORS error on cached resources on chromium-based browsers

Steps to reproduce:

• Ensure magnolia.develop=false
• Clean browser cache before testing
• CORS is enabled for external (uris: /.rest/, /VAADIN/)
• Open SPA page with baseUrl config on chromium-based browsers

Expected results:

•  Icon for green bar is shown, there's no CORS error on console

Actual results:

•  Icon for green bar does not shown, there're CORS errors on console