Hi,
We have just tried to use koa with the following tutorial "Shopify App with Node and React" which is using koa-shopify-auth.
Still have the same problem. Don’t see where it uses the storage access API. When we debug it using the Safari inspect, we see that the cookie is created and then disappeared in a split second and it does not use the local storage.
https://shopify.dev/tutorials/build-a-shopify-app-with-node-and-react/set-up-your-app