diff --git a/.github/workflows/playwright-mock.yml b/.github/workflows/playwright-mock.yml
index 3baae0e307..db3a275b25 100644
--- a/.github/workflows/playwright-mock.yml
+++ b/.github/workflows/playwright-mock.yml
@@ -144,6 +144,16 @@ jobs:
       - name: Verify Chrome is present
         run: google-chrome --version
 
+      # `video: 'on-first-retry'` needs ffmpeg; without it the first retry dies in
+      # browserContext.newPage before the test body runs, so a flaky test loses the
+      # retry that would have recovered it. The CLI can hang after the download
+      # finishes on these runners, so bound it and keep it non-fatal — worst case is
+      # today's behaviour of retrying without video.
+      - name: Install Playwright ffmpeg (best effort)
+        timeout-minutes: 3
+        continue-on-error: true
+        run: timeout -k 10 90 npx playwright install ffmpeg
+
       # The runner's Chrome is an apt package, so its real library dependencies are
       # already satisfied; all `install-deps` adds here are optional CJK/Thai/Cyrillic
       # font packages (~21MB from azure.archive.ubuntu.com). Nothing in CI asserts on
@@ -235,6 +245,12 @@ jobs:
       - name: Verify Chrome is present
         run: google-chrome --version
 
+      # ffmpeg for retry video — see the note in the e2e_shards job.
+      - name: Install Playwright ffmpeg (best effort)
+        timeout-minutes: 3
+        continue-on-error: true
+        run: timeout -k 10 90 npx playwright install ffmpeg
+
       # Optional fonts only — see the note in the e2e_shards job.
       - name: Install optional Playwright font dependencies (best effort)
         timeout-minutes: 4
diff --git a/e2e/specs/mock/quotes.spec.ts b/e2e/specs/mock/quotes.spec.ts
index 4e524b9551..37e2cba038 100644
--- a/e2e/specs/mock/quotes.spec.ts
+++ b/e2e/specs/mock/quotes.spec.ts
@@ -98,6 +98,33 @@ async function doubleClickWord(page: Page, needle: string) {
   await page.mouse.dblclick(point.x, point.y);
 }
 
+/**
+ * Wait for the reply to stop re-rendering before selecting text inside it.
+ *
+ * Distinct from the settle window `QuoteButton` applies to a *selection*: this
+ * is the reply itself still streaming. A markdown re-render swaps out the text
+ * node the selection points at, which collapses it — so a double-click landing
+ * mid-stream loses its selection before the popup can be clicked, and every
+ * `toPass` retry loses the same race rather than recovering from it.
+ *
+ * `sendMessage` resolves on the stream *response*, not on the final render, so
+ * the wait has to be explicit.
+ */
+async function waitForReplyToSettle(page: Page, needle: string) {
+  const readReply = () =>
+    page.evaluate((text) => {
+      const renders = Array.from(document.querySelectorAll('.message-render'));
+      const host = [...renders].reverse().find((el) => (el.textContent ?? '').includes(text));
+      return host?.textContent ?? '';
+    }, needle);
+
+  await expect(async () => {
+    const before = await readReply();
+    await page.waitForTimeout(250);
+    expect(await readReply()).toBe(before);
+  }).toPass({ timeout: 20000 });
+}
+
 /**
  * Triple-click the block containing `needle` with native mouse events, which
  * makes Chromium select that whole block and park the selection's far boundary
@@ -311,6 +338,7 @@ test.describe('quote references', () => {
     const response = await sendMessage(page, 'seed for dblclick');
     expect(response.ok()).toBeTruthy();
     await expect(mockReply(page)).toBeVisible({ timeout: 20000 });
+    await waitForReplyToSettle(page, MOCK_REPLY_TEXT);
 
     // A real double-click selects the word under the cursor. Chromium commits
     // that selection on `dblclick`, AFTER `mouseup` fires, so only a `dblclick`