I follow NextJS documentation on Prefixing defaultLocale however, I’m facing build error when I run yarn build

> Export encountered errors on following paths:
        /: /default
        /_error: /404
        /_error: /500
        /_error: /default/404
        /_error: /default/500
        /about: /default/about
        /apply: /default/apply
        ...

I suspect that it has to do with getStaticProps and locale to fetch some of my content.

export async function getStaticProps({ locale }: { locale: string }) {
  const lang = locale.split("-")[0] as Locale;
  const pageData = apply[lang];
  return {
    props: {
      pageData,
    },
  };
}

I tried to conditionally update the content of lang as such:

const lang = locale !== 'default' ? locale.split("-")[0] as Locale : 'fr' as Locale;

I still get the error.