Ok, I found the problem. I realised that all of the routing was having and issue and after some Googling, I found that it is caused by the way StrictMode works with React Router. in https://serverless-stack.com/chapters/handle-routes-with-react-router.html you need to make sure that the Router component wraps StrictMode, not the other way around.

const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(
  <Router>
    <React.StrictMode>
      <App />
    </React.StrictMode>
  </Router>

Oh wow that’s a good catch @Neil Balcombe. Let me make a note of this so we can fix it in an upcoming release.