diff --git a/e2e/fixtures/router-client/src/components/route-state.tsx b/e2e/fixtures/router-client/src/components/route-state.tsx
index e213d42253..3a03492a35 100644
--- a/e2e/fixtures/router-client/src/components/route-state.tsx
+++ b/e2e/fixtures/router-client/src/components/route-state.tsx
@@ -1,11 +1,18 @@
 'use client';
 
+import { createPortal } from 'react-dom';
 import { useRouter } from 'waku';
 
 export function RouteState() {
   const router = useRouter();
+  const portal = new URLSearchParams(router.query).get('portal') === '1';
   return (
     <>
+      {portal &&
+        createPortal(
+          <div data-testid="portal-marker">portal</div>,
+          document.body,
+        )}
       <p data-testid="route-path">{router.path}</p>
       <p data-testid="route-query">{router.query}</p>
       <p data-testid="route-hash">{router.hash}</p>
diff --git a/e2e/fixtures/router-client/src/pages/start.tsx b/e2e/fixtures/router-client/src/pages/start.tsx
index 29d85da013..b97dda429e 100644
--- a/e2e/fixtures/router-client/src/pages/start.tsx
+++ b/e2e/fixtures/router-client/src/pages/start.tsx
@@ -11,6 +11,11 @@ export default function StartPage() {
           Go next
         </Link>
       </p>
+      <p>
+        <Link to="/next?portal=1" data-testid="go-next-portal">
+          Go next portal
+        </Link>
+      </p>
       <p>
         <Link to="/start?from=query-only" data-testid="go-query-only">
           Go query only
diff --git a/e2e/router-client.spec.ts b/e2e/router-client.spec.ts
index 65769b0d51..9beb4e3618 100644
--- a/e2e/router-client.spec.ts
+++ b/e2e/router-client.spec.ts
@@ -249,6 +249,83 @@ test.describe('router-client', () => {
     expect(await getScrollToCalls(page)).toHaveLength(0);
   });
 
+  test('portal route with popstate churn preserves prior query history entry', async ({
+    page,
+  }) => {
+    const runtimeErrors: string[] = [];
+    let delayedRequestCount = 0;
+    page.on('pageerror', (error) => {
+      runtimeErrors.push(error.message);
+    });
+    page.on('console', (msg) => {
+      if (msg.type() === 'error' && msg.text().includes('removeChild')) {
+        runtimeErrors.push(msg.text());
+      }
+    });
+    await page.route('**/RSC/R/next.txt**', async (route) => {
+      if (route.request().url().includes('query=portal%3D1')) {
+        delayedRequestCount += 1;
+        await new Promise((resolve) => setTimeout(resolve, 200));
+      }
+      await route.continue();
+    });
+
+    await page.goto(`http://localhost:${port}/start`);
+    await waitForHydration(page);
+
+    await page.getByTestId('router-push-query-only').click();
+    await expect(page.getByTestId('route-path')).toHaveText('/start');
+    await expect(page.getByTestId('route-query')).toHaveText('from=query-only');
+
+    await page.getByTestId('go-next-portal').click();
+    await expect(page.getByRole('heading', { name: 'Next' })).toBeVisible();
+    await expect(page.getByTestId('portal-marker')).toBeVisible();
+
+    await page.evaluate(() => {
+      window.history.back();
+      window.history.forward();
+      window.history.back();
+    });
+
+    expect(delayedRequestCount).toBeGreaterThan(0);
+    expect(runtimeErrors).toEqual([]);
+    await expect(page.getByTestId('route-path')).toHaveText('/start');
+    await expect(page.getByTestId('route-query')).toHaveText('from=query-only');
+  });
+
+  test('non-portal route with popstate churn preserves prior query history entry', async ({
+    page,
+  }) => {
+    let delayedRequestCount = 0;
+    await page.route('**/RSC/R/next.txt**', async (route) => {
+      if (route.request().url().includes('query=x%3D1')) {
+        delayedRequestCount += 1;
+        await new Promise((resolve) => setTimeout(resolve, 200));
+      }
+      await route.continue();
+    });
+
+    await page.goto(`http://localhost:${port}/start`);
+    await waitForHydration(page);
+
+    await page.getByTestId('router-push-query-only').click();
+    await expect(page.getByTestId('route-path')).toHaveText('/start');
+    await expect(page.getByTestId('route-query')).toHaveText('from=query-only');
+
+    await page.getByTestId('go-next').click();
+    await expect(page.getByRole('heading', { name: 'Next' })).toBeVisible();
+
+    await page.evaluate(() => {
+      window.history.back();
+      window.history.forward();
+      window.history.back();
+    });
+
+    expect(delayedRequestCount).toBeGreaterThan(0);
+    await expect(page.getByTestId('route-path')).toHaveText('/start');
+    await expect(page.getByTestId('route-query')).toHaveText('from=query-only');
+  });
+
   test('back/forward for path-change history scrolls to top', async ({
     page,
   }) => {