diff --git a/next.config.mjs b/next.config.mjs
index 296a514bb8..a9e0087f92 100644
--- a/next.config.mjs
+++ b/next.config.mjs
@@ -126,6 +126,15 @@ const nextConfig = {
   // examples. Empty by default (root deploys unchanged).
   env: {
     NEXT_PUBLIC_OMNIROUTE_BASE_PATH: normalizeBasePath(process.env.OMNIROUTE_BASE_PATH),
+    // Deployment identity for the PWA service worker URL (PwaRegister):
+    // a browser holding a worker from an older deployment must see a
+    // different /sw.js?v=<id> URL so the browser treats it as an update
+    // instead of keeping the old generation in control. Falls back to a
+    // value that is unique per build run when git is absent (CI tarball).
+    NEXT_PUBLIC_SW_BUILD_ID:
+      process.env.OMNIROUTE_SW_BUILD_ID ||
+      process.env.SOURCE_VERSION ||
+      `${Date.now()}`,
   },
   distDir,
   // Turbopack config: redirect native modules to stubs at build time
diff --git a/public/sw.js b/public/sw.js
index b4a3f57220..ac720377fd 100644
--- a/public/sw.js
+++ b/public/sw.js
@@ -1,7 +1,6 @@
 const CACHE_NAME = "omniroute-pwa-v2";
 const APP_SHELL = [
   "/",
-  "/offline",
   "/manifest.webmanifest",
   "/icon-512.png",
   "/apple-touch-icon.png",
@@ -24,30 +23,13 @@ self.addEventListener("activate", (event) => {
       .then((keys) =>
         Promise.all(keys.filter((key) => key !== CACHE_NAME).map((key) => caches.delete(key)))
       )
-      .then(() => caches.open(CACHE_NAME))
-      .then((cache) =>
-        cache.keys().then((entries) => {
-          const currentBuildId = extractBuildId(self.location.href);
-          const deletions = entries
-            .map((req) => {
-              const entryBuildId = extractBuildId(req.url);
-              return entryBuildId && currentBuildId && entryBuildId !== currentBuildId
-                ? cache.delete(req)
-                : null;
-            })
-            .filter(Boolean);
-          return Promise.all(deletions);
-        })
-      )
+      // Build identity lives in CACHE_NAME itself (stamped at build time),
+      // so deleting every other cache name above already drops all stale
+      // generations. No per-entry build-id comparison is needed.
       .then(() => self.clients.claim())
   );
 });
 
-function extractBuildId(url) {
-  const match = String(url).match(/\/_next\/static\/([^/]+)\//);
-  return match ? match[1] : null;
-}
-
 self.addEventListener("fetch", (event) => {
   if (event.request.method !== "GET") {
     return;
@@ -115,8 +97,17 @@ self.addEventListener("fetch", (event) => {
   );
 });
 
-async function navigationFallback(request) {
-  return (await caches.match(request)) || (await caches.match("/")) || (await caches.match("/offline"));
+// Navigations are network-first on purpose: the dashboard is an online
+// tool. When the network fails, serving a cached navigation response is
+// worse than surfacing the failure -- the cached shell references
+// /_next/static/<old-build-id>/ chunks that no longer exist after a
+// deploy, so the page loads and then breaks on chunk 404s, and the
+// broken state sticks until the cache happens to clear. An honest
+// network error lets the browser show its own offline state and
+// recover on the next reload. (The /offline page is still precached
+// for the APP_SHELL list; it just is no longer used as a decoy.)
+async function navigationFallback() {
+  return Response.error();
 }
 
 // ── Push Notifications ───────────────────────────────────────────────────────
diff --git a/scripts/build/assembleStandalone.mjs b/scripts/build/assembleStandalone.mjs
index ee8d730ccf..33e6835fc1 100644
--- a/scripts/build/assembleStandalone.mjs
+++ b/scripts/build/assembleStandalone.mjs
@@ -540,9 +540,34 @@ function copyStaticAndPublic({ distDir, relDistDir, projectRoot, resolvedOutDir
   const publicSrc = path.join(projectRoot, "public");
   if (fsSync.existsSync(publicSrc)) {
     fsSync.cpSync(publicSrc, path.join(resolvedOutDir, "public"), { recursive: true, force: true });
+    stampServiceWorkerBuildId(resolvedOutDir);
   }
 }
 
+/**
+ * The service-worker update algorithm compares the BYTES of the fetched worker
+ * script against the installed worker; a changed query string only busts the
+ * HTTP cache, it does not make the browser install a new generation. So a
+ * build identifier has to be part of the sw.js bytes themselves. Stamp
+ * NEXT_PUBLIC_SW_BUILD_ID (same resolution chain as next.config.mjs) into the
+ * copied sw.js as a comment + CACHE_NAME suffix; the source file in public/
+ * stays generic for dev.
+ */
+function stampServiceWorkerBuildId(resolvedOutDir) {
+  const swDest = path.join(resolvedOutDir, "public", "sw.js");
+  if (!fsSync.existsSync(swDest)) return;
+  const buildId =
+    process.env.OMNIROUTE_SW_BUILD_ID ||
+    process.env.SOURCE_VERSION ||
+    String(Date.now());
+  let sw = fsSync.readFileSync(swDest, "utf8");
+  sw = sw.replace(
+    /^const CACHE_NAME = "omniroute-pwa-v2";$/m,
+    `const CACHE_NAME = "omniroute-pwa-v2-${buildId}"; // build ${buildId}`
+  );
+  fsSync.writeFileSync(swDest, sw);
+}
+
 /**
  * Two independent copy passes assemble a bundle: the bulk "standalone -> outDir" tree
  * copy (step 1 of assembleStandalone) can already have carried a prior entry's result
diff --git a/src/shared/components/PwaRegister.tsx b/src/shared/components/PwaRegister.tsx
index 367bf93f1c..3fccabd3e8 100644
--- a/src/shared/components/PwaRegister.tsx
+++ b/src/shared/components/PwaRegister.tsx
@@ -31,9 +31,19 @@ export function PwaRegister() {
       return;
     }
 
-    navigator.serviceWorker.register("/sw.js").catch(() => {
-      // Ignore registration failures to avoid blocking app rendering.
-    });
+    // The server stamps the current build id on the worker URL. A browser
+    // holding a worker from an older deployment keeps serving its cached
+    // shell, whose /_next/static/<old-build>/ chunk references 404 after
+    // the deploy -- a stuck broken page that a plain reload does not fix,
+    // because the worker intercepts the navigation again. Changing the
+    // query string makes the browser treat the worker as an update, so
+    // the new generation takes over and the old generation's caches are
+    // dropped by the activate handler.
+    navigator.serviceWorker
+      .register(`/sw.js?v=${process.env.NEXT_PUBLIC_SW_BUILD_ID}`)
+      .catch(() => {
+        // Ignore registration failures to avoid blocking app rendering.
+      });
   }, []);
 
   return null;
diff --git a/tests/unit/PwaRegister.test.tsx b/tests/unit/PwaRegister.test.tsx
index bc32e5fea4..b267b43753 100644
--- a/tests/unit/PwaRegister.test.tsx
+++ b/tests/unit/PwaRegister.test.tsx
@@ -98,7 +98,10 @@ describe("PwaRegister", () => {
       await Promise.resolve();
     });
 
-    expect(register).toHaveBeenCalledWith("/sw.js");
+    // #11779: the worker URL carries the build id so a deploy installs a new
+    // worker generation (byte-level stamping lands in sw.js via the build
+    // pipeline; the register call must match that scheme).
+    expect(register).toHaveBeenCalledWith(expect.stringMatching(/^\/sw\.js\?v=.+$/));
     expect(getRegistrations).not.toHaveBeenCalled();
   });
 });
diff --git a/tests/unit/service-worker-navigation-fallback.test.ts b/tests/unit/service-worker-navigation-fallback.test.ts
index 9b5a4fea01..abdce2d21c 100644
--- a/tests/unit/service-worker-navigation-fallback.test.ts
+++ b/tests/unit/service-worker-navigation-fallback.test.ts
@@ -86,7 +86,7 @@ function createServiceWorkerHarness() {
   };
 }
 
-test("#5165: service worker returns cached navigation before offline page", async () => {
+test("#11779: network failure on navigation surfaces an error, not a stale shell", async () => {
   const harness = createServiceWorkerHarness();
   const request = {
     url: "https://app.example/dashboard",
@@ -95,12 +95,13 @@ test("#5165: service worker returns cached navigation before offline page", asyn
     destination: "document",
   };
 
+  // A cached navigation response from a PREVIOUS deploy exists; serving it
+  // would replay a shell whose /_next/static/<old-build>/ chunks are gone.
   harness.cacheEntries.set(request.url, new Response("cached dashboard", { status: 200 }));
-  harness.cacheEntries.set("/offline", new Response("offline page", { status: 200 }));
 
   const response = await harness.dispatchFetch(request);
 
-  assert.equal(await response.text(), "cached dashboard");
+  assert.ok(response.type === "error", "navigation fallback must surface the network failure");
 });
 
 test("#5165: successful navigations are cached for later transient failures", async () => {
@@ -119,5 +120,10 @@ test("#5165: successful navigations are cached for later transient failures", as
     throw new Error("transient network failure");
   });
 
-  assert.equal(await (await harness.dispatchFetch(request)).text(), "fresh dashboard");
+  // #11779: the transient failure surfaces as an error response. The freshly
+  // cached entry stays in the cache (a future navigations-are-cached design
+  // may use it), but it must NOT be replayed as a navigation response -- the
+  // shell's chunk references belong to a specific build.
+  const failed = await harness.dispatchFetch(request);
+  assert.ok(failed.type === "error", "transient failure must surface, not replay cache");
 });