diff --git a/apps/desktop/src/pages/ConversationPage.tsx b/apps/desktop/src/pages/ConversationPage.tsx
index 4a2572c..72aa4bf 100644
--- a/apps/desktop/src/pages/ConversationPage.tsx
+++ b/apps/desktop/src/pages/ConversationPage.tsx
@@ -3,7 +3,7 @@ import { extractErrorCode } from '@chat-app/shared/i18n';
 import { lazy, Suspense, useCallback, useEffect, useMemo, useRef, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { useParams } from 'react-router-dom';
-import { Virtuoso, type VirtuosoHandle } from 'react-virtuoso';
+import { Virtuoso, type VirtuosoHandle, type IndexLocationWithAlign } from 'react-virtuoso';
 
 import { ComposerActionsMenu } from '../components/ComposerActionsMenu';
 import { ConversationHeader } from '../components/ConversationHeader';
@@ -471,16 +471,28 @@ export function ConversationPage() {
   // previous visit to this chat AND the user wasn't sticking to the
   // bottom, restore the saved row index (clamped to the current row
   // count in case the cache was trimmed).
-  const initialTopMostIndex = useMemo(() => {
+  const initialTopMostIndex = useMemo<number | IndexLocationWithAlign>(() => {
     const saved = savedPositionRef.current;
     if (saved && !saved.stickToBottom) {
-      return Math.max(0, Math.min(saved.topmostIndex, virtuosoRows.length - 1));
+      // Restore the row the user was reading, pinned to the TOP of the
+      // viewport — that's the anchor the index was captured at
+      // (handleRangeChanged stores range.startIndex).
+      const idx = Math.max(0, Math.min(saved.topmostIndex, virtuosoRows.length - 1));
+      return { index: idx, align: 'start' };
     }
-    return virtuosoRows.length - 1;
-    // virtuosoRows.length changes when the conversation loads — that's the
-    // intentional trigger so a freshly-loaded chat anchors to the bottom
-    // on first paint. We deliberately don't re-derive this on every row
-    // append; Virtuoso owns scroll position from that point on.
+    // Bottom case (the common one): anchor the LAST row to the END (bottom)
+    // edge of the viewport. This is the fix for the "jumps once on chat
+    // switch" bug: a plain numeric index aligns the row to the TOP, so
+    // react-virtuoso paints with estimated row heights, then measures the
+    // real (taller) heights of the dynamic bubbles (avatars, attachments,
+    // multi-line text, reactions) and corrects scrollTop — a visible jump on
+    // every mount. `align: 'end'` pins the bottom edge instead, so the
+    // post-measurement height growth happens above the fold and the viewport
+    // stays put. This is react-virtuoso's canonical "start at the bottom" form.
+    return { index: 'LAST', align: 'end' };
+    // virtuosoRows.length flipping 0 -> >0 is the intentional trigger so a
+    // freshly-loaded chat anchors on first paint; we deliberately don't
+    // re-derive on every row append — Virtuoso owns scroll position after.
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [virtuosoRows.length > 0]);