seems to be the cause. If rewrite pages/auth/[[...path]] as follows, it will not redirect

export default function Auth() {
  // if the user visits a page that is not handled by us (like /auth/random), then we redirect them back to the auth page.
  useEffect(() => {
    if (canHandleRoute([ThirdPartyEmailPasswordPreBuiltUI]) === false) {
      console.log('red to auth');
      redirectToAuth();
    }
  }, []);

  return <div>aaaaaaaa</div>;
}