fix: Clear convertedAmount when amount or currency is manually modified

src/libs/TransactionUtils/index.ts

@@ -699,10 +699,19 @@ function getUpdatedTransaction({
     if (Object.hasOwn(transactionChanges, 'amount') && typeof transactionChanges.amount === 'number') {
         updatedTransaction.modifiedAmount = isFromExpenseReport || isUnReportedExpense ? -transactionChanges.amount : transactionChanges.amount;
         shouldStopSmartscan = true;
+        // Clear convertedAmount when amount is manually modified to prevent stale conversion data
+        // from being used during export (the server will recalculate if needed)
+        // Use null instead of undefined because Onyx.merge treats undefined as no-op
+        updatedTransaction.convertedAmount = null;
     }
     if (Object.hasOwn(transactionChanges, 'currency')) {
         updatedTransaction.modifiedCurrency = transactionChanges.currency;
         shouldStopSmartscan = true;
+        // Clear convertedAmount when currency is manually modified to prevent incorrect
+        // currency conversion being applied during export (fixes issue where manually entered
+        // amounts in a different currency were being re-converted)
+        // Use null instead of undefined because Onyx.merge treats undefined as no-op
+        updatedTransaction.convertedAmount = null;
     }
 
     if (Object.hasOwn(transactionChanges, 'merchant')) {

src/types/onyx/Transaction.ts

@@ -441,7 +441,7 @@ type Transaction = OnyxCommon.OnyxValueWithOfflineFeedback<
         accountant?: Accountant;
 
         /** The transaction converted amount in report's currency */
-        convertedAmount?: number;
+        convertedAmount?: number | null;
 
         /** The transaction tax amount */
         taxAmount?: number;

tests/unit/TransactionUtilsTest.ts

@@ -425,6 +425,50 @@ describe('TransactionUtils', () => {
                 merchant: CONST.RED_BRICK_ROAD_PENDING_ACTION.UPDATE,
             });
         });
+
+        it('should clear convertedAmount when currency is changed to prevent incorrect export conversion', () => {
+            // Given: a transaction with a converted amount (simulating a foreign currency transaction)
+            const transaction = generateTransaction({
+                amount: -4500, // $45.00 USD
+                currency: CONST.CURRENCY.USD,
+                convertedAmount: -6285, // C$62.85 CAD (server-calculated conversion)
+            });
+
+            // When: user manually changes the currency to CAD
+            const updatedTransaction = TransactionUtils.getUpdatedTransaction({
+                transaction,
+                isFromExpenseReport: true,
+                transactionChanges: {currency: 'CAD'},
+            });
+
+            // Then: convertedAmount should be cleared (set to null, not undefined, because
+            // Onyx.merge treats undefined as no-op) to prevent stale conversion data
+            // being incorrectly applied during export
+            expect(updatedTransaction.modifiedCurrency).toBe('CAD');
+            expect(updatedTransaction.convertedAmount).toBeNull();
+        });
+
+        it('should clear convertedAmount when amount is manually changed to prevent incorrect export conversion', () => {
+            // Given: a transaction with a converted amount
+            const transaction = generateTransaction({
+                amount: -4500, // $45.00 USD
+                currency: CONST.CURRENCY.USD,
+                convertedAmount: -6285, // C$62.85 CAD
+            });
+
+            // When: user manually changes the amount
+            const updatedTransaction = TransactionUtils.getUpdatedTransaction({
+                transaction,
+                isFromExpenseReport: true,
+                transactionChanges: {amount: 6285}, // C$62.85
+            });
+
+            // Then: convertedAmount should be cleared (set to null, not undefined, because
+            // Onyx.merge treats undefined as no-op) since the manual amount
+            // is the final value and shouldn't be re-converted during export
+            expect(updatedTransaction.modifiedAmount).toBe(-6285);
+            expect(updatedTransaction.convertedAmount).toBeNull();
+        });
     });
 
     describe('getTransactionType', () => {