가상계좌 결제에서 면세 금액(taxFreeAmount)이 처리되지 않는 이슈

paymentData: {
  "method": "CARD",
  "taxFreeAmount": 44700,
  "amount": {
    "currency": "KRW",
    "value": 66470
  },
  "orderId": "20251217-8732A",
  "orderName": "[면세] 홍삼 배도라지즙 6… 외 1건",
  "customerName": "리아드(Riad)'s teacher(riad)",
  "successUrl": "....",
  "failUrl": "...",
  "card": {
    "useEscrow": false,
    "flowMode": "DEFAULT",
    "useCardPoint": false,
    "useAppCardOnly": false
  }
}

$responseJson
array(37)
mId: "tkn_nstore"
lastTransactionKey: "txrd_a01kcn14tzgj0029135nythbfqx"
paymentKey: "tkn_n20251217110929z2GK8"
orderId: "20251217-8732A"
...
currency: "KRW"
totalAmount: 66470
balanceAmount: 66470
suppliedAmount: 19791
vat: 1979
taxFreeAmount: 44700 < 정상확인
method: "간편결제"
version: "2022-11-16"
metadata: null

paymentData: {
  "method": "VIRTUAL_ACCOUNT",
  "taxFreeAmount": 44700,
  "amount": {
    "currency": "KRW",
    "value": 66470
  },
  "orderId": "20251217-22C46",
  "orderName": "[면세] 홍삼 배도라지즙 6… 외 1건",
  "customerName": "리아드(Riad)'s teacher(riad)",
  "successUrl": "...",
  "failUrl": "...",
  "virtualAccount": {
    "validHours": 24,
    "useEscrow": false
  }
}

$responseJson
array(37)
mId: "tkn_nstore"
lastTransactionKey: "txrd_a01kcn191686d4vm7czpnqga6rm"
paymentKey: "tkn_n20251217111159wobL5"
orderId: "20251217-22C46"
...
currency: "KRW"
totalAmount: 66470
balanceAmount: 66470
suppliedAmount: 60427
vat: 6043
taxFreeAmount: 0 <-- 0 으로 전달받음
method: "가상계좌"
version: "2022-11-16"
metadata: null