First load of CodeSanbox when logged in bug

🐛 bug report

Description of the problem

I have a simple fetch in vanilla ts codesanbox, which loads some data from api and displays it on page.

//index.ts

async function fetchData(url: string) {
  const response = await fetch(url);
  return response.json();
}

fetchData("https://jsonplaceholder.typicode.com/todos").then((data) => {
  const app = document.getElementById("app");

  if (app)
    app.innerHTML = `
    <h1>Simple fetch example</h1><p><pre>${JSON.stringify(
      data,
      null,
      2
    )}</pre></p>`;
});

When I am logged in to my codesandbox account, on first load it doesn't work as expected.
It shows content for a moment and then clears it. If I'm not logged in, everything works as expected.

Issue #4128 might be related

To Reproduce

Try to copy/paste code provided above to codesandbox and test first load while logged in.

Your Environment

Start by reproducing the provided index.ts vanilla TypeScript fetch example on the first load while logged in, then compare it with the logged-out behavior. Review issue #4128 for related context; done means the fetched page content remains visible on first load for logged-in users without breaking the logged-out case.