If you tag a foreign currency payment directly from a bank account to the relevant foreign currency invoice the exchange rate is set by QF using xe.com and most likely you’ll find after allocation there is a discrepancy between the two exchange rates used for the invoice and the payment.
To fix a discrepancy not being generated the payment should be allocated directly from the invoice raised as this allows to override the exchange rate set by xe.com and this way you should be able to get your payment to match the invoice,; but that will not always be possible refer to “Four decimal places” Four decimal place exchange rate.
After manually creating the payment directly from the invoice; there will be a duplication of the payment in the relevant bank account…copy and paste the description that your bank provided and move to your manual entry of the payment…then delete the duplicate payment received via your bank feed or uploading a bank statement.
PRE-CHECK before allocation - Amend INVOICE exchange rate to equal the PAYMENT sent prior to allocation’, as this is not editable after a payment has been allocated…of course possible by deleting the payment and starting again! Many goes and eventually found a way!!
Usually if using the QF/xe.com allocation method there would be a few pennies difference; but rather strange exchange rate calculated for your transaction for such a large discrepancy to be reported.