diff --git a/changelog.d/1281-traffic-issue-fix.md b/changelog.d/1281-traffic-issue-fix.md
index ade62efe4..2c4d1900c 100644
--- a/changelog.d/1281-traffic-issue-fix.md
+++ b/changelog.d/1281-traffic-issue-fix.md
@@ -1,2 +1,4 @@
 - Hold rendering only for animated content (asturksever, #1281).
 - Exercise current vector road sources and published camera bounds in Traffic fixture QA (asturksever, #1281).
+- Establish browser-level foreground visibility for Traffic QA and reject hidden-page samples (asturksever, #1281).
+- Supply CORS headers on cross-origin traffic fixtures and report browser exceptions without disabling browser security (asturksever, #1281).
diff --git a/scripts/qa-traffic.mjs b/scripts/qa-traffic.mjs
index 5da4b7db7..bb00596ce 100644
--- a/scripts/qa-traffic.mjs
+++ b/scripts/qa-traffic.mjs
@@ -82,6 +82,10 @@ const sleep = (ms) => new Promise((r) => setTimeout(r, ms));
 
 /** Enable traffic + teleport, then poll the layer until settled. */
 async function settleTraffic(page, view, { minCount = 1, timeoutS = 30 } = {}) {
+  // The app deliberately stops rendering hidden pages. Programmatic camera
+  // changes do not activate a headful window the way a real UI click does.
+  await page.bringToFront();
+  await page.waitForFunction(() => document.visibilityState === 'visible');
   return page.evaluate(async (v, minC, tS) => {
     const gev = window.__godsEyeView;
     const dm = gev.dataManager;
@@ -99,6 +103,7 @@ async function settleTraffic(page, view, { minCount = 1, timeoutS = 30 } = {}) {
     });
     let s = null;
     for (let i = 0; i < tS; i++) {
+      if (document.visibilityState !== 'visible') throw new Error('Traffic QA page became hidden; rendering is intentionally paused');
       await new Promise((r) => setTimeout(r, 1000));
       s = mod.getStats();
       // Retained roads from the previous city can satisfy count/loading before
@@ -140,7 +145,7 @@ async function main() {
       '--no-sandbox', '--disable-setuid-sandbox',
       ...(!HEADFUL ? ['--use-gl=angle', '--use-angle=swiftshader'] : []),
       '--disable-backgrounding-occluded-windows',
-      '--disable-dev-shm-usage', '--disable-web-security',
+      '--disable-dev-shm-usage',
       '--disable-background-timer-throttling', '--disable-renderer-backgrounding',
       '--window-size=1440,900',
     ],
@@ -149,6 +154,10 @@ async function main() {
   let exitCode = 0;
   try {
     const page = await browser.newPage();
+    // Keep this visible-page regression deterministic even if the OS starts
+    // Chrome minimized. Use browser focus emulation, not patched DOM getters.
+    const focusSession = await page.createCDPSession();
+    await focusSession.send('Emulation.setFocusEmulationEnabled', { enabled: true });
     const onFixture = (request) => {
       const response = fixtureResponse(request);
       if (response) void request.respond(response); else void request.continue();
@@ -162,6 +171,9 @@ async function main() {
       if (req.url().includes('/api/tomtom/flow/')) flowRequests.push(req.url());
     });
     const trafficLogs = [];
+    const pageErrors = [];
+    page.on('pageerror', error => { pageErrors.push(error.message); console.error('PAGE ERROR:', error.message); });
+    page.on('console', message => { if (message.type() === 'error') console.error('BROWSER ERROR:', message.text()); });
     page.on('console', (msg) => {
       const t = msg.text();
       if (t.includes('[Data:Traffic]')) trafficLogs.push(t);
@@ -319,6 +331,7 @@ async function main() {
       await sleep(1000);
       await page.screenshot({ path: path.join(SHOTS_DIR, 'traffic-sim-keyless.png') });
     }
+    record('BROWSER: no uncaught page exceptions', pageErrors.length === 0, pageErrors.join('; '));
   } catch (e) {
     console.error('\x1b[31mHarness error:\x1b[0m', e);
     exitCode = 3;
diff --git a/scripts/traffic-fixtures.mjs b/scripts/traffic-fixtures.mjs
index af51487db..2f94993cc 100644
--- a/scripts/traffic-fixtures.mjs
+++ b/scripts/traffic-fixtures.mjs
@@ -1,7 +1,9 @@
 import { PbfWriter } from 'pbf';
 
+const corsHeaders = { 'access-control-allow-origin': '*' };
 const json = (body) => ({
   status: 200,
+  headers: corsHeaders,
   contentType: 'application/json',
   body: JSON.stringify(body),
 });
@@ -80,6 +82,7 @@ export function trafficFixtureResponse(request) {
       return {
         status: 200,
         contentType: 'application/octet-stream',
+        headers: corsHeaders,
         body: flatTerrain,
       };
     throw new Error(`Unexpected terrain fixture request: ${url.pathname}`);
@@ -93,6 +96,7 @@ export function trafficFixtureResponse(request) {
     return {
       status: 200,
       contentType: 'application/x-protobuf',
+      headers: corsHeaders,
       body: trafficFixtureTile(Number(flow[1]), true),
     };
   if (url.hostname !== 'tiles.openfreemap.org') return null;
@@ -109,6 +113,7 @@ export function trafficFixtureResponse(request) {
   return {
     status: 200,
     contentType: 'application/x-protobuf',
+    headers: corsHeaders,
     body: trafficFixtureTile(Number(road[1])),
   };
 }
diff --git a/src/tooling/trafficFixtures.test.mjs b/src/tooling/trafficFixtures.test.mjs
index 308c0aaa6..e02b959e7 100644
--- a/src/tooling/trafficFixtures.test.mjs
+++ b/src/tooling/trafficFixtures.test.mjs
@@ -33,9 +33,9 @@ test('traffic fixtures provide aligned current road tiles and partial flow cover
 
 test('fixture TileJSON and every road/flow request stay on intercepted sources', () => {
   const request = (url) => trafficFixtureResponse({ url: () => url });
-  const metadata = JSON.parse(
-    request('https://tiles.openfreemap.org/planet').body,
-  );
+  const tileJson = request('https://tiles.openfreemap.org/planet');
+  assert.equal(tileJson.headers['access-control-allow-origin'], '*');
+  const metadata = JSON.parse(tileJson.body);
   const tileUrl = metadata.tiles[0]
     .replace('{z}', '14')
     .replace('{x}', '935')