React Web App Callback Fails Using iOS

Following the example from the Auth0 repo: auth0-react-samples:
https://github.com/auth0-samples/auth0-react-samples/tree/master/04-Authorization

I have modified the server so the react files are served from the node server (as in production), instead of using the react-scripts from create-react-app.
app.use(express.static(path.resolve(__dirname, '..', './client/build')));
There seems to be a bug that when the callback is called from Auth0 servers back to the single page react app, the handleAuthentication function does not receive the JWT token:

{ handleAuthentication(props); return <Callback {...props}/> }}/>

On a laptop, the callback runs, and the page is refreshed with correct authorization to the page. But on iOS web browser it does not, and hangs at the Callback loading svg. It seems like the callback is ignored. Both laptop and iOS work fine running locally using react scripts, but production build version does not work for iOS.

Looking for suggestions and advice.
Thanks

Hi mate - did you find a solution to this?
@legends200