My code on the dev server

function Home(props) {
  console.log("Hello")
  return (
    <ul>
      {props.user.map((user) => (
        <li key={user.id}>{user.email}</li>
      ))}
    </ul>
  )
}

export default Home

export async function getStaticProps() {
  const res = await fetch('https://jsonplaceholder.typicode.com/users')
  const data = await res.json()

  return {
    props: {
      user: data,
    },
    revalidate: 10,
  }
}

Then I run npm run build and start the real server with npm run start

Now if I change my JSX from

<li key={user.id}>{user.email}</li>

to

<li key={user.id}>{user.username}</li>

And wait some time, then the page still looks like before, nothing has changed -> It still shows user.email and not user.username