How to work with router.isFallback on production builds?

[gglnx]

I'm using next.js 9.3 and getStaticPaths with fallback: true. In my page component I'm checking for isFallback and rendering a spinner on fallback and an 404 error page if props are missing:

const Location: React.FC<LocationProps> = ({ location }) => {
  const router = useRouter();

  // Fallback
  if (router.isFallback) {
    return (
      <Spinner />
    );
  }

  // No location found
  if (!location) {
    return <Error statusCode={404} />;
  }

While development opening an uncached pages shows the spinner and after loading everything my component, but on production the 404 error page is shown instead of the spinner.

How can I make sure that my component is build with the spinner as default?

[Timer]

How are you deploying your application?

[gglnx]

Git checkout on the server, then next build and pm2 with next start.