Payment method getting defaulted in the Refund attributes screen while applying refunds in AR

We are using Refunds functionality in AR which automatically creates the Payment Request in Payables and we make the payments to customers as suppliers.

Before applying RPC 4 patcset the payment methods ue to come as Null in the Refund attrbutes section.User use to fill it.After appying the RPC 4 pathset the Payment method is gettinbg defaulted to 'WIRE'.We are not syure what chnaged the behavior.We generally use CHECK as the refund documnt and the payment method.So everytime the user has to ensure that the paynemt method is updatd to CHECK.

There is no defaulting rules set up for AR in the payment set ups.