Reverse Charge Mechanism (RCM) under GST - Goods and Services Tax - GST

Dear Experts, We are receiving services of renting of immovable property from unregistered person against which we are liable to pay GST under RCM. Let suppose, we have made an advance payment to supplier on 08/04/2025 as rent for the month of April 2025. Whether we have to do record RCM on payment voucher recorded in books on 08/04/2025? However, the unregistered supplier is submitting an invoice for April 2025 to us during the month of May 2025 (Let say 02/05/2025). Now, what will be the time limit for issuing self-invoice against such transaction? Further, On which date/entry, RCM liability to be recorded in books i.e. on the date on which payment has been made to supplier (08/04/2025) or date of self-invoicing? Thanks