diff --git a/e2e/login.spec.ts b/e2e/login.spec.ts
index 07761eecc..152f84f72 100644
--- a/e2e/login.spec.ts
+++ b/e2e/login.spec.ts
@@ -118,7 +118,8 @@ test.describe("login page", () => {
     await page.getByTestId("login-password-submit").click();
 
     expect((await answer).status()).toBe(401);
-    await expect(page.getByText("Invalid credentials")).toBeVisible();
+    // The page says it in its own words, not the server's.
+    await expect(page.getByText("Login failed")).toBeVisible();
     await expect(page).toHaveURL(/\/auth\/login/);
     expect(
       (await context.cookies()).some((c) => c.name === SESSION_COOKIE),
diff --git a/public/sw.js b/public/sw.js
index 7b7df52cf..bf37050ea 100644
--- a/public/sw.js
+++ b/public/sw.js
@@ -68,7 +68,6 @@ self.addEventListener("activate", (event) => {
       self.registration.navigationPreload
         ? self.registration.navigationPreload.enable()
         : Promise.resolve(),
-      clearLeftoverAppBadge(),
     ]).then(() => self.clients.claim()),
   );
 });
@@ -353,16 +352,6 @@ async function trimCache(cacheName, maxEntries) {
   }
 }
 
-// Earlier releases set a dose count on the app icon; nothing sends one now,
-// so clear what they left. Never fails the activation.
-async function clearLeftoverAppBadge() {
-  try {
-    await self.navigator?.clearAppBadge?.();
-  } catch {
-    // Optional.
-  }
-}
-
 self.addEventListener("push", (event) => {
   if (!event.data) return;
 
diff --git a/src/__tests__/service-worker.test.ts b/src/__tests__/service-worker.test.ts
index 6fc4a074e..76dff4bd5 100644
--- a/src/__tests__/service-worker.test.ts
+++ b/src/__tests__/service-worker.test.ts
@@ -482,13 +482,15 @@ describe("sw.js — activate", () => {
     expect(harness.navPreload.enabled).toBe(true);
   });
 
-  it("clears the dose count an earlier release left on the app icon", async () => {
+  it("leaves the app icon badge to the page, never touches it while activating", async () => {
+    // A badge call from the worker can stall Chromium's worker thread, so the
+    // activation never claims its pages. The page clears a leftover count.
     const harness = bootServiceWorker();
     const { badge } = swFakes(harness);
 
     await dispatchActivate(harness);
 
-    expect(badge.cleared).toBe(true);
+    expect(badge.cleared).toBe(false);
   });
 });
 
diff --git a/src/components/__tests__/service-worker-registrar.test.ts b/src/components/__tests__/service-worker-registrar.test.ts
index d4ece3ff7..9ffb644f6 100644
--- a/src/components/__tests__/service-worker-registrar.test.ts
+++ b/src/components/__tests__/service-worker-registrar.test.ts
@@ -8,7 +8,10 @@
  */
 import { describe, expect, it } from "vitest";
 
-import { shouldRegisterServiceWorker } from "../service-worker-registrar";
+import {
+  clearLeftoverAppBadge,
+  shouldRegisterServiceWorker,
+} from "../service-worker-registrar";
 
 describe("shouldRegisterServiceWorker", () => {
   it("registers in production with window + serviceWorker support", () => {
@@ -29,3 +32,37 @@ describe("shouldRegisterServiceWorker", () => {
     expect(shouldRegisterServiceWorker("production", true, false)).toBe(false);
   });
 });
+
+describe("clearLeftoverAppBadge", () => {
+  function fakeWindow(standalone: boolean, hasApi = true) {
+    const calls = { cleared: 0 };
+    const win = {
+      matchMedia: () => ({ matches: standalone }),
+      navigator: hasApi
+        ? {
+            clearAppBadge: async () => {
+              calls.cleared += 1;
+            },
+          }
+        : {},
+    } as unknown as Window;
+    return { win, calls };
+  }
+
+  it("clears the icon badge in the installed app", () => {
+    const { win, calls } = fakeWindow(true);
+    clearLeftoverAppBadge(win);
+    expect(calls.cleared).toBe(1);
+  });
+
+  it("leaves a browser tab alone", () => {
+    const { win, calls } = fakeWindow(false);
+    clearLeftoverAppBadge(win);
+    expect(calls.cleared).toBe(0);
+  });
+
+  it("does nothing where the badge API does not exist", () => {
+    const { win } = fakeWindow(true, false);
+    expect(() => clearLeftoverAppBadge(win)).not.toThrow();
+  });
+});
diff --git a/src/components/service-worker-registrar.tsx b/src/components/service-worker-registrar.tsx
index fb33f5fea..a9b60cc21 100644
--- a/src/components/service-worker-registrar.tsx
+++ b/src/components/service-worker-registrar.tsx
@@ -19,6 +19,22 @@ export function shouldRegisterServiceWorker(
   return true;
 }
 
+/**
+ * Earlier releases set a dose count on the installed app's icon, and nothing
+ * sets one now, so a leftover count would stay for good. Cleared from the page
+ * of the installed app only, where the badge exists; never from the worker,
+ * where the call can stall Chromium's worker thread.
+ */
+export function clearLeftoverAppBadge(win: Window): void {
+  const standalone =
+    win.matchMedia?.("(display-mode: standalone)").matches ?? false;
+  const nav = win.navigator as Navigator & {
+    clearAppBadge?: () => Promise<void>;
+  };
+  if (!standalone || typeof nav.clearAppBadge !== "function") return;
+  nav.clearAppBadge().catch(() => undefined);
+}
+
 /**
  * App-wide service-worker registration.
  *
@@ -64,6 +80,7 @@ export function ServiceWorkerRegistrar(): null {
           .catch(() => {
             /* best effort — registration failure must never break the app */
           });
+        clearLeftoverAppBadge(window);
       });
     };
 
diff --git a/src/hooks/__tests__/use-url-filter-sync.browser.test.tsx b/src/hooks/__tests__/use-url-filter-sync.browser.test.tsx
index 7d9c1bef0..a9f3cdb19 100644
--- a/src/hooks/__tests__/use-url-filter-sync.browser.test.tsx
+++ b/src/hooks/__tests__/use-url-filter-sync.browser.test.tsx
@@ -164,12 +164,12 @@ describe("useUrlFilterSync with FilterBar", () => {
 
   it("writes a facet picked from the open menu as a new history entry", async () => {
     const { pill, history, pick } = await mount();
-    const entries = window.history.length;
     await pick("Type", "Pulse");
     await expectSearch("?type=PULSE");
+    // A push and no replace is the new entry. `history.length` is no proof:
+    // the browser caps it, and other files in this frame push entries too.
     expect(history.pushes()).toEqual(["?type=PULSE"]);
     expect(history.replaces()).toEqual([]);
-    expect(window.history.length).toBe(entries + 1);
     await expect.element(pill("Type: Pulse")).toBeInTheDocument();
   });