No transaction occurs until payment. Use removeStoreCreditFromOrder(code: $code) to remove a pending balance.
A balance has one currency, shown in currencyCode. It can only pay for an order in the same currency. If the currencies differ, applyStoreCreditToOrder returns a StoreCreditError and the order is not changed. If the order currency changes after the balance was applied, the balance stays on the order with amountDeducted 0, and addPaymentToOrderWithStoreCredit returns a PaymentFailedError without charging anything. The shopper must remove that balance with removeStoreCreditFromOrder before paying.
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