When you make an international payment, the money is debited from your credit card account on a real-time basis. However, at the backend (between banks) the settlement can take upto 10 days. Ideally, the merchant should send the settlement on the same day to the same foreign exchange rate, but if there’s any delay from them, then the exchange rate of the settlement day can be more or less than the rate of exchange when you made the payment.
If the new rate is more, then the difference gets debited (gets deducted) from your credit card account.
If the new rate is lesser, then the difference gets credited (comes to you) to your credit card account.
This is called “Fx Adjustment” and can show on the transactions page.