diff --git a/packages/cli/src/registry/captionLastGroup.chromium.test.ts b/packages/cli/src/registry/captionLastGroup.chromium.test.ts
new file mode 100644
index 0000000000..a602b862af
--- /dev/null
+++ b/packages/cli/src/registry/captionLastGroup.chromium.test.ts
@@ -0,0 +1,71 @@
+import { afterAll, beforeAll, describe, expect, it } from "vitest";
+import { readFileSync } from "node:fs";
+import { createRequire } from "node:module";
+import puppeteer, { type Browser } from "puppeteer-core";
+
+const executablePath = process.env.PUPPETEER_EXECUTABLE_PATH;
+const componentHtml = readFileSync(
+  new URL(
+    "../../../../registry/components/caption-highlight/caption-highlight.html",
+    import.meta.url,
+  ),
+  "utf8",
+);
+const gsapScript = readFileSync(
+  createRequire(new URL("../../../core/package.json", import.meta.url)).resolve(
+    "gsap/dist/gsap.min.js",
+  ),
+  "utf8",
+);
+
+/** Scaled demo words: the last group opens before the old 7.95 s cap and its last word ends after it. */
+const STRETCH = 1.15;
+const LAST_WORD_START_S = 7.3 * STRETCH;
+const LAST_WORD_END_S = 7.7 * STRETCH;
+
+function stretchedComponent(): string {
+  const wordsStart = componentHtml.indexOf("var WORDS = [");
+  const wordsEnd = componentHtml.indexOf("];", wordsStart);
+  const words = componentHtml
+    .slice(wordsStart, wordsEnd)
+    .replace(/(start|end): ([\d.]+)/g, (_, key, value) => `${key}: ${Number(value) * STRETCH}`);
+  return (componentHtml.slice(0, wordsStart) + words + componentHtml.slice(wordsEnd)).replace(
+    /<script src="https:[^"]*gsap[^"]*"><\/script>/,
+    `<script>${gsapScript}</script>`,
+  );
+}
+
+describe.runIf(executablePath)("caption-highlight last group in Chromium", () => {
+  let browser: Browser;
+
+  beforeAll(async () => {
+    browser = await puppeteer.launch({ executablePath, args: ["--no-sandbox"] });
+  });
+
+  afterAll(async () => {
+    await browser?.close();
+  });
+
+  async function lastGroupVisibleAt(time: number): Promise<boolean> {
+    const page = await browser.newPage();
+    try {
+      await page.setContent(stretchedComponent());
+      return await page.evaluate((t) => {
+        const timeline = (
+          window as unknown as { __timelines: Record<string, { seek(t: number): void }> }
+        ).__timelines["caption-highlight"];
+        timeline!.seek(t);
+        const groups = document.querySelectorAll(".hl-group");
+        const style = getComputedStyle(groups[groups.length - 1]!);
+        return style.visibility !== "hidden" && Number(style.opacity) > 0;
+      }, time);
+    } finally {
+      await page.close();
+    }
+  }
+
+  it("shows the last phrase from its first word to just before its last word ends", async () => {
+    expect(await lastGroupVisibleAt(LAST_WORD_START_S)).toBe(true);
+    expect(await lastGroupVisibleAt(LAST_WORD_END_S - 0.05)).toBe(true);
+  });
+});
diff --git a/packages/cli/src/registry/registryComponents.test.ts b/packages/cli/src/registry/registryComponents.test.ts
index 4f3cfa1969..0352fa464b 100644
--- a/packages/cli/src/registry/registryComponents.test.ts
+++ b/packages/cli/src/registry/registryComponents.test.ts
@@ -56,6 +56,18 @@ describe("registry components", () => {
     expect(invalidMedia).toEqual([]);
   });
 
+  it("never caps a caption's last group at a fixed demo-length constant", () => {
+    const capped: string[] = [];
+
+    for (const entry of readdirSync(componentsDir, { withFileTypes: true })) {
+      if (!entry.isDirectory() || !entry.name.startsWith("caption-")) continue;
+      const html = readFileSync(join(componentsDir, entry.name, `${entry.name}.html`), "utf8");
+      if (/nextStart\s*=[^;]*:\s*\d+(?:\.\d+)?;/.test(html)) capped.push(entry.name);
+    }
+
+    expect(capped).toEqual([]);
+  });
+
   it("ships demos without source-less media", async () => {
     const invalidMedia: string[] = [];
 
diff --git a/registry/components/caption-clip-wipe/caption-clip-wipe.html b/registry/components/caption-clip-wipe/caption-clip-wipe.html
index 9b5d55e599..41d882b460 100644
--- a/registry/components/caption-clip-wipe/caption-clip-wipe.html
+++ b/registry/components/caption-clip-wipe/caption-clip-wipe.html
@@ -153,7 +153,8 @@
         var GROUPS = RAW_GROUPS.map(function (pair, gi) {
           var ws = pair[0],
             we = pair[1];
-          var nextStart = gi + 1 < RAW_GROUPS.length ? WORDS[RAW_GROUPS[gi + 1][0]].start : 8.0;
+          var nextStart =
+            gi + 1 < RAW_GROUPS.length ? WORDS[RAW_GROUPS[gi + 1][0]].start : Infinity;
           var gEnd = Math.min(WORDS[we].end + 0.5, nextStart - 0.05);
           return { wordStart: ws, wordEnd: we, start: WORDS[ws].start, end: gEnd };
         });
diff --git a/registry/components/caption-glitch-rgb/caption-glitch-rgb.html b/registry/components/caption-glitch-rgb/caption-glitch-rgb.html
index e44a67674f..fe212755ec 100644
--- a/registry/components/caption-glitch-rgb/caption-glitch-rgb.html
+++ b/registry/components/caption-glitch-rgb/caption-glitch-rgb.html
@@ -204,7 +204,7 @@
           var ws = pair[0];
           var we = pair[1];
           var nextStart =
-            gi + 1 < RAW_GROUPS.length ? TRANSCRIPT[RAW_GROUPS[gi + 1][0]].start : 8.0;
+            gi + 1 < RAW_GROUPS.length ? TRANSCRIPT[RAW_GROUPS[gi + 1][0]].start : Infinity;
           var end = Math.min(TRANSCRIPT[we].end + 0.24, nextStart - 0.04);
           return { wordStart: ws, wordEnd: we, start: TRANSCRIPT[ws].start, end: end };
         });
diff --git a/registry/components/caption-highlight/caption-highlight.html b/registry/components/caption-highlight/caption-highlight.html
index 2617005887..615084e01f 100644
--- a/registry/components/caption-highlight/caption-highlight.html
+++ b/registry/components/caption-highlight/caption-highlight.html
@@ -178,7 +178,8 @@
         var GROUPS = RAW_GROUPS.map(function (pair, gi) {
           var ws = pair[0],
             we = pair[1];
-          var nextStart = gi + 1 < RAW_GROUPS.length ? WORDS[RAW_GROUPS[gi + 1][0]].start : 8.0;
+          var nextStart =
+            gi + 1 < RAW_GROUPS.length ? WORDS[RAW_GROUPS[gi + 1][0]].start : Infinity;
           var gEnd = Math.min(WORDS[we].end + 0.5, nextStart - 0.05);
           return { wordStart: ws, wordEnd: we, start: WORDS[ws].start, end: gEnd };
         });
diff --git a/registry/components/caption-particle-burst/caption-particle-burst.html b/registry/components/caption-particle-burst/caption-particle-burst.html
index 2df4604db8..15ab9c5f06 100644
--- a/registry/components/caption-particle-burst/caption-particle-burst.html
+++ b/registry/components/caption-particle-burst/caption-particle-burst.html
@@ -174,7 +174,8 @@
         var GROUPS = RAW_GROUPS.map(function (pair, gi) {
           var ws = pair[0],
             we = pair[1];
-          var nextStart = gi + 1 < RAW_GROUPS.length ? WORDS[RAW_GROUPS[gi + 1][0]].start : 8.0;
+          var nextStart =
+            gi + 1 < RAW_GROUPS.length ? WORDS[RAW_GROUPS[gi + 1][0]].start : Infinity;
           var gEnd = Math.min(WORDS[we].end + 0.35, nextStart - 0.05);
           return { wordStart: ws, wordEnd: we, start: WORDS[ws].start, end: gEnd };
         });