diff --git a/Dockerfile.test b/Dockerfile.test
index a20d795b1..d6e83f9c2 100644
--- a/Dockerfile.test
+++ b/Dockerfile.test
@@ -53,7 +53,12 @@ ENV CONTAINER=true
 # Install chrome-headless-shell for deterministic BeginFrame rendering.
 # This lightweight Chrome binary supports HeadlessExperimental.beginFrame.
 # Install to ~/.cache/puppeteer/ where resolveHeadlessShellPath() looks.
-RUN npx --yes @puppeteer/browsers install chrome-headless-shell@stable \
+#
+# Pinned to a specific build (NOT @stable) so the regression-test golden
+# baselines in packages/producer/tests/*/output/output.mp4 stay reproducible.
+# Each Chrome stable bump shifts pixel output enough to fail PSNR. Bump this
+# version together with regenerating baselines via `docker:test:update`.
+RUN npx --yes @puppeteer/browsers install chrome-headless-shell@148.0.7778.167 \
       --path /root/.cache/puppeteer \
     && find /root/.cache/puppeteer/chrome-headless-shell -name "chrome-headless-shell" -type f \
     && echo "chrome-headless-shell installed"
diff --git a/packages/producer/src/regression-harness.ts b/packages/producer/src/regression-harness.ts
index 5b9d3c153..ad4f991fc 100644
--- a/packages/producer/src/regression-harness.ts
+++ b/packages/producer/src/regression-harness.ts
@@ -1079,16 +1079,19 @@ async function runTestSuite(
         videoMetadata.durationSeconds,
         snapshotMetadata.durationSeconds,
       );
+      const fps = fpsToNumber(suite.meta.renderConfig.fps);
+      // Container duration includes audio padding past the last video frame
+      // (e.g. many-cuts: 5.654s container vs 5.6s of video). At i=99 the
+      // raw container duration maps to a frame index past nb_frames, and
+      // ffmpeg's PSNR filter emits no `average:` line for a non-existent
+      // frame. Subtract one frame interval so the last checkpoint always
+      // lands on a frame the video stream actually contains.
+      const sampleDuration = Math.max(0, videoDuration - 1 / fps);
 
       const minPsnrForMode = resolveMinPsnrForMode(options.mode, suite.meta.minPsnr);
       for (let i = 0; i < 100; i++) {
-        const time = (videoDuration * i) / 100;
-        const psnr = psnrAtCheckpoint(
-          renderedOutputPath,
-          snapshotVideoPath,
-          time,
-          fpsToNumber(suite.meta.renderConfig.fps),
-        );
+        const time = (sampleDuration * i) / 100;
+        const psnr = psnrAtCheckpoint(renderedOutputPath, snapshotVideoPath, time, fps);
         visualCheckpoints.push({
           time,
           psnr,
diff --git a/packages/producer/tests/style-1-prod/output/output.mp4 b/packages/producer/tests/style-1-prod/output/output.mp4
index 65819d2f9..696141418 100644
--- a/packages/producer/tests/style-1-prod/output/output.mp4
+++ b/packages/producer/tests/style-1-prod/output/output.mp4
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:6aba60a5a3919132986e785b89f4b3434d23d337d95958a515b1fe2e11906721
-size 5154704
+oid sha256:d2fb75093153c6f03ade0848121b0072a4b91934935cba970d42883d456d9383
+size 8389204
diff --git a/packages/producer/tests/style-12-prod/output/compiled.html b/packages/producer/tests/style-12-prod/output/compiled.html
index 93ab16160..aa64d9f9f 100644
--- a/packages/producer/tests/style-12-prod/output/compiled.html
+++ b/packages/producer/tests/style-12-prod/output/compiled.html
@@ -492,7 +492,7 @@
   var __hfEscapeAttr = function(value) {
     return (value + "").replace(/\\/g, "\\\\").replace(/"/g, "\\\"");
   };
-  var __hfRootSelector = null || (__hfCompId
+  var __hfRootSelector = "[data-composition-id=\"mondrian-bg\"]" || (__hfCompId
     ? '[data-composition-id="' + __hfEscapeAttr(__hfCompId) + '"]'
     : "");
   var __hfRoot = null;
@@ -754,7 +754,8 @@
   var __hfRun = function() {
     try {
       (function(document, gsap, window, __hyperframes) {
-(function () {
+
+      (function () {
         const tl = gsap.timeline({ paused: true });
 
         tl.to(".bar-1", { left: "100%", duration: 0.45, ease: "expo.out" }, 1.1);
@@ -764,6 +765,7 @@
 
         window.__timelines["mondrian-bg"] = tl;
       })();
+    
       }).call(window, __hfScopedDocument, __hfScopedGsap, __hfScopedWindow, __hfScopedHyperframes);
     } catch (_err) {
       console.error(__hfErrorLabel, __hfCompId, _err);
@@ -782,7 +784,7 @@
   var __hfEscapeAttr = function(value) {
     return (value + "").replace(/\\/g, "\\\\").replace(/"/g, "\\\"");
   };
-  var __hfRootSelector = null || (__hfCompId
+  var __hfRootSelector = "[data-composition-id=\"mondrian-colors\"]" || (__hfCompId
     ? '[data-composition-id="' + __hfEscapeAttr(__hfCompId) + '"]'
     : "");
   var __hfRoot = null;
@@ -1044,7 +1046,8 @@
   var __hfRun = function() {
     try {
       (function(document, gsap, window, __hyperframes) {
-(function () {
+
+      (function () {
         const TRANSCRIPT = [
           { text: "We", start: 0.14, end: 0.239 },
           { text: "asked", start: 0.28, end: 0.459 },
@@ -1181,6 +1184,7 @@
 
         window.__timelines["mondrian-colors"] = tl;
       })();
+    
       }).call(window, __hfScopedDocument, __hfScopedGsap, __hfScopedWindow, __hfScopedHyperframes);
     } catch (_err) {
       console.error(__hfErrorLabel, __hfCompId, _err);
@@ -1199,7 +1203,7 @@
   var __hfEscapeAttr = function(value) {
     return (value + "").replace(/\\/g, "\\\\").replace(/"/g, "\\\"");
   };
-  var __hfRootSelector = null || (__hfCompId
+  var __hfRootSelector = "[data-composition-id=\"mondrian-captions\"]" || (__hfCompId
     ? '[data-composition-id="' + __hfEscapeAttr(__hfCompId) + '"]'
     : "");
   var __hfRoot = null;
@@ -1461,7 +1465,8 @@
   var __hfRun = function() {
     try {
       (function(document, gsap, window, __hyperframes) {
-(function () {
+
+      (function () {
         const TRANSCRIPT = [
           { text: "We", start: 0.14, end: 0.239 },
           { text: "asked", start: 0.28, end: 0.459 },
@@ -1551,6 +1556,7 @@
 
         window.__timelines["mondrian-captions"] = tl;
       })();
+    
       }).call(window, __hfScopedDocument, __hfScopedGsap, __hfScopedWindow, __hfScopedHyperframes);
     } catch (_err) {
       console.error(__hfErrorLabel, __hfCompId, _err);
diff --git a/packages/producer/tests/style-12-prod/output/output.mp4 b/packages/producer/tests/style-12-prod/output/output.mp4
index 57ffe0b9c..1dce2a6c3 100644
--- a/packages/producer/tests/style-12-prod/output/output.mp4
+++ b/packages/producer/tests/style-12-prod/output/output.mp4
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:04de22fa8fe2bd25a40ffb6577fcf6da7d0317a44ed753c291f238f1ae048ccc
-size 8714819
+oid sha256:b217384799298e6e828bbeac09dc44c699db64c2902c6af7bc229df5dd73c101
+size 11091047