Not receiving expiration_date, expiration_date_ms, and expiration_date_pst in receipt validation response

I'm accessing the receipt after a successful in-app subscription (by checking SKPaymentTransactionStatePurchased
state). After I verified this receipt, in the receipt verification response "expirationdate", "expirationdatems", and "expirationdatepst" are are missing under "receipt". Why is that?

(As a workaround I tried to get the last object of latestreceipt_info and refer its expiration date. But this data is referring to the last subscription before the current one. So I cannot find the required expiration date there.)

How can I resolve this and retrieve expiration date of the subscription purchased just now?