diff --git a/app/mobile/engagement/page.tsx b/app/mobile/engagement/page.tsx
index 6008c67..80c7093 100644
--- a/app/mobile/engagement/page.tsx
+++ b/app/mobile/engagement/page.tsx
@@ -172,35 +172,48 @@ export default function MobileEngagementPage() {
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [sortKey]);
 
-  // D-04 fallback: the mobile shell's <main> is overflow-y-auto, so Next.js's
-  // built-in scrollRestoration (which targets window) doesn't help. Persist the
-  // inner scroll position across navigations via sessionStorage so back from
-  // /mobile/engagement/[userId] restores the row the user tapped.
+  // D-04 fallback: scroll restoration via sessionStorage. The actual scroll
+  // container differs by viewport — `<main>` has overflow-y-auto, but in some
+  // configurations the document scrolls instead. Listen on both, save the one
+  // that's non-zero, and restore both.
   const restoredScrollRef = useRef(false);
   useEffect(() => {
-    const main = document.querySelector('main');
-    if (!main) return;
     let raf = 0;
+    const save = () => {
+      const main = document.querySelector('main');
+      const mainTop = main?.scrollTop ?? 0;
+      const winTop  = window.scrollY || document.documentElement.scrollTop || 0;
+      sessionStorage.setItem('mobile-engagement-scroll', JSON.stringify({ main: mainTop, win: winTop }));
+    };
     const onScroll = () => {
       if (raf) return;
-      raf = requestAnimationFrame(() => {
-        raf = 0;
-        sessionStorage.setItem('mobile-engagement-list-scroll', String(main.scrollTop));
-      });
+      raf = requestAnimationFrame(() => { raf = 0; save(); });
     };
-    main.addEventListener('scroll', onScroll, { passive: true });
+    window.addEventListener('scroll', onScroll, { passive: true });
+    const main = document.querySelector('main');
+    main?.addEventListener('scroll', onScroll, { passive: true });
     return () => {
-      main.removeEventListener('scroll', onScroll);
+      window.removeEventListener('scroll', onScroll);
+      main?.removeEventListener('scroll', onScroll);
       if (raf) cancelAnimationFrame(raf);
     };
   }, []);
   useEffect(() => {
     if (restoredScrollRef.current) return;
     if (usersLoading || users.length === 0) return;
-    const main = document.querySelector('main');
-    if (!main) return;
-    const saved = sessionStorage.getItem('mobile-engagement-list-scroll');
-    if (saved) main.scrollTop = parseInt(saved, 10);
+    const raw = sessionStorage.getItem('mobile-engagement-scroll');
+    if (!raw) { restoredScrollRef.current = true; return; }
+    try {
+      const { main: mainTop, win: winTop } = JSON.parse(raw) as { main: number; win: number };
+      // Defer one frame so layout has settled with the new rows in place.
+      requestAnimationFrame(() => {
+        const main = document.querySelector('main');
+        if (main && mainTop) main.scrollTop = mainTop;
+        if (winTop) window.scrollTo(0, winTop);
+      });
+    } catch {
+      /* corrupt entry — ignore */
+    }
     restoredScrollRef.current = true;
   }, [usersLoading, users.length]);