If the amounts don't match on a document payment in a foreign currency, this is usually caused by the dual currency setting being filled in under the company settings.
Solution
Open Company → Settings → Legislation and find the Dual currency field. Leave the field empty.
ℹ️ The dual currency setting is only used in exceptional cases — for example, when a country transitions to the euro and both the original and new currency need to appear on documents at the same time. You don't need it for regular foreign currency accounting.