next.js: Custom server renderToHTML does not work with next 13.4

Link to the code that reproduces this issue or a replay of the bug

https://github.com/thilohaas/nextjs-custom-server/tree/main https://codesandbox.io/p/github/thilohaas/nextjs-custom-server/main

To Reproduce

1. Start a new nextjs project with npx create-next-app@latest
2. Add a server.js

const { createServer } = require('http');
const { parse } = require('url');
const next = require('next');

const dev = process.env.NODE_ENV !== "production";
const hostname = 'localhost';
const port = process.env.PORT || 3001;
// when using middleware `hostname` and `port` must be provided below
const app = next({ hostname, port, dev });
const handle = app.getRequestHandler();

app.prepare().then(() => {
  createServer(async (req, res) => {
    try {
      const parsedUrl = parse(req.url, true);
      const { pathname, query } = parsedUrl;

      if (pathname.startsWith('/_next') || pathname.startsWith('/__next')) {
        await handle(req, res, parsedUrl);
      } else {
        const html = await app.renderToHTML(req, res, pathname, query);
        res.end(html);
      }
    } catch (err) {
      console.error('Error occurred handling', req.url, err);
      res.statusCode = 500;
      res.end('internal server error');
    }
  }).listen(port, (err) => {
    if (err) throw err;
    console.log(`> Ready on http://${hostname}:${port}`);
  });
});

1. Change the package.json dev script to: "dev": "node server.js",
2. run npm run dev
3. open http://localhost:3001

Current vs. Expected behavior

I expect it to display the welcome page but instead i get an error from the next server:

Error: Invariant ensurePage called outside render worker

Verify canary release

• I verified that the issue exists in the latest Next.js canary release

Provide environment information

Operating System:
      Platform: linux
      Arch: x64
      Version: #1 SMP PREEMPT_DYNAMIC Sun Aug  6 20:05:33 UTC 2023
    Binaries:
      Node: 16.17.0
      npm: 8.15.0
      Yarn: 1.22.19
      pnpm: 7.1.0
    Relevant Packages:
      next: 13.4.20-canary.16
      eslint-config-next: N/A
      react: 18.2.0
      react-dom: 18.2.0
      typescript: 5.1.3
    Next.js Config:
      output: N/A

Which area(s) are affected? (Select all that apply)

Not sure

Additional context

No response