diff --git a/vehicle-data-platform/apps/web/src/api/client.test.ts b/vehicle-data-platform/apps/web/src/api/client.test.ts
index 6bd5c3e8..23ab42c9 100644
--- a/vehicle-data-platform/apps/web/src/api/client.test.ts
+++ b/vehicle-data-platform/apps/web/src/api/client.test.ts
@@ -1,6 +1,6 @@
 import { afterEach, expect, test, vi } from 'vitest';
 import { api } from './client';
-import { PLATFORM_UNAUTHORIZED_EVENT } from '../v2/auth/session';
+import { getAccessToken, PLATFORM_UNAUTHORIZED_EVENT, setAccessToken } from '../v2/auth/session';
 
 afterEach(() => {
   vi.restoreAllMocks();
@@ -28,11 +28,51 @@ test('a protected 401 terminates the client session but login validation errors
 
   await expect(api.monitorSummary()).rejects.toThrow('访问令牌无效');
   expect(unauthorized).toHaveBeenCalledTimes(1);
+  expect(getAccessToken()).toBe('');
   await expect(api.session()).rejects.toThrow('访问令牌无效');
   expect(unauthorized).toHaveBeenCalledTimes(1);
   window.removeEventListener(PLATFORM_UNAUTHORIZED_EVENT, unauthorized);
 });
 
+test('parallel protected 401 responses invalidate one client session exactly once', async () => {
+  setAccessToken('expired-parallel-token');
+  const unauthorized = vi.fn();
+  window.addEventListener(PLATFORM_UNAUTHORIZED_EVENT, unauthorized);
+  vi.spyOn(globalThis, 'fetch').mockResolvedValue({
+    ok: false,
+    status: 401,
+    json: async () => ({ error: { message: '访问令牌已过期' } })
+  } as Response);
+
+  const results = await Promise.allSettled([api.monitorSummary(), api.metricCatalog(), api.opsHealth()]);
+
+  expect(results.every((result) => result.status === 'rejected')).toBe(true);
+  expect(unauthorized).toHaveBeenCalledTimes(1);
+  expect(getAccessToken()).toBe('');
+  window.removeEventListener(PLATFORM_UNAUTHORIZED_EVENT, unauthorized);
+});
+
+test('a delayed 401 from an old token cannot terminate a newer login', async () => {
+  setAccessToken('old-token');
+  const unauthorized = vi.fn();
+  window.addEventListener(PLATFORM_UNAUTHORIZED_EVENT, unauthorized);
+  let resolveResponse!: (response: Response) => void;
+  vi.spyOn(globalThis, 'fetch').mockReturnValue(new Promise<Response>((resolve) => { resolveResponse = resolve; }));
+
+  const oldRequest = api.monitorSummary();
+  setAccessToken('new-token');
+  resolveResponse({
+    ok: false,
+    status: 401,
+    json: async () => ({ error: { message: '旧令牌已过期' } })
+  } as Response);
+
+  await expect(oldRequest).rejects.toThrow('旧令牌已过期');
+  expect(unauthorized).not.toHaveBeenCalled();
+  expect(getAccessToken()).toBe('new-token');
+  window.removeEventListener(PLATFORM_UNAUTHORIZED_EVENT, unauthorized);
+});
+
 test('durable alert APIs keep versioned actions, rules and notification reads explicit', async () => {
   const fetchMock = vi.spyOn(globalThis, 'fetch').mockResolvedValue({ ok: true, json: async () => ({ data: {}, traceId: 'trace-alert', timestamp: 1 }) } as Response);
   await api.alertEventsV2({ status: 'unprocessed', limit: 20, offset: 0 });
diff --git a/vehicle-data-platform/apps/web/src/api/client.ts b/vehicle-data-platform/apps/web/src/api/client.ts
index 8153e520..a51e59ed 100644
--- a/vehicle-data-platform/apps/web/src/api/client.ts
+++ b/vehicle-data-platform/apps/web/src/api/client.ts
@@ -90,7 +90,7 @@ async function request<T>(path: string, init?: RequestInit): Promise<T> {
   const requestInit = token ? { ...init, headers: withAuthorization(init?.headers, token) } : init;
   const response = await fetch(path, requestInit);
   if (!response.ok) {
-    if (response.status === 401 && token && path !== '/api/v2/session') notifyUnauthorizedSession();
+    if (response.status === 401 && token && path !== '/api/v2/session') notifyUnauthorizedSession(token);
     throw new Error(await responseErrorMessage(response));
   }
   const envelope = (await response.json()) as ApiEnvelope<T>;
diff --git a/vehicle-data-platform/apps/web/src/v2/auth/session.test.ts b/vehicle-data-platform/apps/web/src/v2/auth/session.test.ts
index 0cb912d9..f543088f 100644
--- a/vehicle-data-platform/apps/web/src/v2/auth/session.test.ts
+++ b/vehicle-data-platform/apps/web/src/v2/auth/session.test.ts
@@ -1,5 +1,5 @@
-import { afterEach, expect, test } from 'vitest';
-import { canAdminister, canOperate, clearAccessToken, getAccessToken, setAccessToken } from './session';
+import { afterEach, expect, test, vi } from 'vitest';
+import { canAdminister, canOperate, clearAccessToken, getAccessToken, notifyUnauthorizedSession, PLATFORM_UNAUTHORIZED_EVENT, setAccessToken } from './session';
 
 afterEach(() => {
   window.sessionStorage.clear();
@@ -20,3 +20,18 @@ test('role helpers follow the server permission hierarchy', () => {
   expect(canAdminister({ name: 'o', role: 'operator', authMode: 'enforce' })).toBe(false);
   expect(canAdminister({ name: 'a', role: 'admin', authMode: 'enforce' })).toBe(true);
 });
+
+test('invalidates only the currently active rejected token', () => {
+  const unauthorized = vi.fn();
+  window.addEventListener(PLATFORM_UNAUTHORIZED_EVENT, unauthorized);
+  setAccessToken('new-token');
+
+  expect(notifyUnauthorizedSession('old-token')).toBe(false);
+  expect(getAccessToken()).toBe('new-token');
+  expect(notifyUnauthorizedSession('new-token')).toBe(true);
+  expect(getAccessToken()).toBe('');
+  expect(notifyUnauthorizedSession('new-token')).toBe(false);
+  expect(unauthorized).toHaveBeenCalledTimes(1);
+
+  window.removeEventListener(PLATFORM_UNAUTHORIZED_EVENT, unauthorized);
+});
diff --git a/vehicle-data-platform/apps/web/src/v2/auth/session.ts b/vehicle-data-platform/apps/web/src/v2/auth/session.ts
index 49f060ab..bf87a228 100644
--- a/vehicle-data-platform/apps/web/src/v2/auth/session.ts
+++ b/vehicle-data-platform/apps/web/src/v2/auth/session.ts
@@ -23,8 +23,11 @@ export function clearAccessToken() {
   window.sessionStorage.removeItem(TOKEN_KEY);
 }
 
-export function notifyUnauthorizedSession() {
+export function notifyUnauthorizedSession(rejectedToken: string) {
+  if (!rejectedToken || getAccessToken() !== rejectedToken) return false;
+  clearAccessToken();
   window.dispatchEvent(new Event(PLATFORM_UNAUTHORIZED_EVENT));
+  return true;
 }
 
 export function canOperate(session: PlatformSession) {