What versions & operating system are you using?

Wrangler 4.40.3, node 22, macos

Please provide a link to a minimal reproduction

https://github.com/tumes/my-ssrless-astro-app

Describe the Bug

EDIT: My original post was incorrect, this seems to have been an issue beginning with wrangler 4.40.3. I have adjusted all references to mention 4.40.3 instead of 4.41.0 though it is present in both.

Deploying a built Astro app or running npm run preview locally for a prerendered page or a server island seems to be busted on wrangler 4.40.3. When you attempt to navigate to a prerendered page or include a server island, the following is all that is rendered:

[object Object]

Reverting to wrangler 4.40.0 fixes this. Running astro dev does not exhibit this issue, only when running dev via wrangler, but since the built app is what is deployed, it ends up reflecting the bug in production.

Please provide any relevant error logs

No errors are present, wrangler reports the routes as a 200 OK.