diff --git a/src/pages/inbox/report/ReportActionsList.tsx b/src/pages/inbox/report/ReportActionsList.tsx
index 4c6d19e4fd3e..923623ee0641 100644
--- a/src/pages/inbox/report/ReportActionsList.tsx
+++ b/src/pages/inbox/report/ReportActionsList.tsx
@@ -695,11 +695,26 @@ function ReportActionsList({
         return isExpenseReport(report) || isIOUReport(report) || isInvoiceReport(report);
     }, [parentReportAction, report, sortedVisibleReportActions]);
 
+    // Precompute a reportActionID → index map so renderItem can resolve the real index in O(1)
+    // instead of scanning sortedVisibleReportActions with indexOf on every render.
+    const actionIndexMap = useMemo(() => {
+        const map = new Map<string, number>();
+        for (const [i, action] of sortedVisibleReportActions.entries()) {
+            map.set(action.reportActionID, i);
+        }
+        return map;
+    }, [sortedVisibleReportActions]);
+
     const renderItem = useCallback(
         ({item: reportAction, index}: ListRenderItemInfo<OnyxTypes.ReportAction>) => {
             const originalReportID = getOriginalReportID(report.reportID, reportAction, reportActionsFromOnyx);
             const showPreviousMessagesButton = reportAction.actionName === CONST.REPORT.ACTIONS.TYPE.CREATED && !!isConciergeSidePanel && !!showHiddenHistory && !!hasPreviousMessages;
 
+            // Use the action's actual index in sortedVisibleReportActions rather than the FlashList-provided index,
+            // because useFlashListScrollKey may slice the data for deep-link scroll positioning, making the
+            // FlashList index offset from the full array and causing wrong displayAsGroup computation.
+            const safeIndex = actionIndexMap.get(reportAction.reportActionID) ?? index;
+
             return (
                 <>
                     <ReportActionsListItemRenderer
@@ -711,8 +726,8 @@ function ReportActionsList({
                         transactionThreadReport={transactionThreadReport}
                         linkedReportActionID={linkedReportActionID}
                         displayAsGroup={
-                            !isConsecutiveChronosAutomaticTimerAction(sortedVisibleReportActions, index, chatIncludesChronosWithID(reportAction?.reportID), isOffline) &&
-                            isConsecutiveActionMadeByPreviousActor(sortedVisibleReportActions, index, isOffline)
+                            !isConsecutiveChronosAutomaticTimerAction(sortedVisibleReportActions, safeIndex, chatIncludesChronosWithID(reportAction?.reportID), isOffline) &&
+                            isConsecutiveActionMadeByPreviousActor(sortedVisibleReportActions, safeIndex, isOffline)
                         }
                         shouldHideThreadDividerLine={shouldHideThreadDividerLine}
                         shouldDisplayNewMarker={reportAction.reportActionID === unreadMarkerReportActionID}
@@ -754,6 +769,7 @@ function ReportActionsList({
             isOffline,
             transactionThreadReport,
             linkedReportActionID,
+            actionIndexMap,
             sortedVisibleReportActions,
             shouldHideThreadDividerLine,
             unreadMarkerReportActionID,
@@ -847,14 +863,14 @@ function ReportActionsList({
                         <View key={action.reportActionID}>
                             {renderItem({
                                 item: action,
-                                index: sortedVisibleReportActions.indexOf(action),
+                                index: actionIndexMap.get(action.reportActionID) ?? 0,
                             } as ListRenderItemInfo<OnyxTypes.ReportAction>)}
                         </View>
                     ))}
                 </StaticReportActionsPreview>
             </>
         );
-    }, [hideComposer, initialNumToRender, renderItem, shouldShowReportRecipientLocalTime, sortedVisibleReportActions, styles]);
+    }, [actionIndexMap, hideComposer, initialNumToRender, renderItem, shouldShowReportRecipientLocalTime, sortedVisibleReportActions, styles]);
 
     const onStartReached = useCallback(() => {
         if (!isSearchTopmostFullScreenRoute()) {