buyerIdentity null on checkout extension

Hi guys, im using Checkout extension for “purchase.thank-you.block.render”.

Want to ask, why sometimes user failed/getting null when getting customer info from api.buyerIdentity.customer?

const api = useApi();
const customer = api?.buyerIdentity?.customer?.current;

Not everytime getting this, but sometimes user got this issues. Anyone knows what happens?

If the customer isn’t logged in, then it’s a “guest” session and there isn’t any information to provide.

but i already setup customer need to sign-in first before checkout. It should not checkout as guest right?