solution simply as it can be

Author: sumo-slonik

src/libs/actions/IOU.ts

@@ -3630,7 +3630,7 @@ function getTrackExpenseInformation(params: GetTrackExpenseInformationParams): T
         transactionParams: {
             amount: isExpenseReport(iouReport) ? -amount : amount,
             currency,
-            reportID: shouldUseMoneyReport && iouReport ? iouReport.reportID : undefined,
+            reportID: shouldUseMoneyReport && iouReport ? iouReport.reportID : CONST.REPORT.UNREPORTED_REPORT_ID,
             comment,
             created,
             merchant,

src/libs/actions/Transaction.ts

@@ -595,15 +595,11 @@ function changeTransactionsReport(transactionIDs: string[], reportID: string) {
     const failureData: OnyxUpdate[] = [];
     const successData: OnyxUpdate[] = [];
 
-    // If a transaction doesn't have an assigned report, it is considered an unreported transaction,
-    // so we can assign it the default ID equal to the Unreported report ID.
-    const transactionsWithDefaultIds = transactions.map((transaction) => ({
-        ...transaction,
-        reportID: transaction.reportID ?? CONST.REPORT.UNREPORTED_REPORT_ID,
-    }));
-
-    transactionsWithDefaultIds.forEach((transaction) => {
+    transactions.forEach((transaction) => {
         const oldIOUAction = getIOUActionForReportID(transaction.reportID, transaction.transactionID);
+        if (!transaction.reportID) {
+            return;
+        }
 
         const oldReportID = transaction.reportID;
         const oldReport = allReports?.[`${ONYXKEYS.COLLECTION.REPORT}${oldReportID}`];

src/pages/AddUnreportedExpense.tsx

@@ -38,7 +38,7 @@ function AddUnreportedExpense({route}: AddUnreportedExpensePageType) {
         if (!transactions) {
             return [];
         }
-        return Object.values(transactions || {}).filter((item) => item?.reportID === '0' || !item?.reportID);
+        return Object.values(transactions || {}).filter((item) => item?.reportID === '0');
     }
 
     const [transactions = []] = useOnyx(ONYXKEYS.COLLECTION.TRANSACTION, {