As the payments are made in arrears the payment on 31 December 20X1 will have paid off any interest accrued in the year. Therefore at the reporting date, there will be no interest outstanding and so the current liability will not show any interest payment.
If the payment was in advance then we would make this separation of the interest payable within current liabilities, as the first thing it will pay is the interest that was accrued in the prior year.