diff --git a/packages/client/src/components/ChatView.tsx b/packages/client/src/components/ChatView.tsx
index a329a7e6b..f25e55f53 100644
--- a/packages/client/src/components/ChatView.tsx
+++ b/packages/client/src/components/ChatView.tsx
@@ -332,8 +332,11 @@ const ChatViewInner = forwardRef<ChatViewHandle, Props>(function ChatView({ sess
     // ping-pong bug). A pin sets scrollTop, not scrollHeight, so the next
     // onChange sees no growth and the loop cannot sustain itself.
     onChange: () => {
+      // Virtualizer may fire notify after jsdom teardown (suite-level
+      // unhandled "window is not defined"). Bail when unmounted / no DOM.
+      if (typeof window === "undefined") return;
       const el = scrollRef.current;
-      if (!el) return;
+      if (!el || !el.isConnected) return;
       const prevH = lastScrollHeightRef.current;
       const nextH = el.scrollHeight;
       if (nextH === prevH) return;
diff --git a/scripts/__tests__/test-up-port-derivation.test.mjs b/scripts/__tests__/test-up-port-derivation.test.mjs
index c2d20711f..f21abff39 100644
--- a/scripts/__tests__/test-up-port-derivation.test.mjs
+++ b/scripts/__tests__/test-up-port-derivation.test.mjs
@@ -159,33 +159,38 @@ describe("test-up.sh state file", () => {
 });
 
 describe.skipIf(!hasDocker())("compose interpolation (requires docker)", () => {
-  it("published port tracks listen port + container env", () => {
-    const out = execFileSync(
-      "docker",
-      [
-        "compose",
-        "-f",
-        path.join(DOCKER_DIR, "compose.yml"),
-        "-f",
-        path.join(DOCKER_DIR, "compose.test.yml"),
-        "config",
-      ],
-      {
-        cwd: DOCKER_DIR,
-        env: { ...process.env, DASHBOARD_PORT: "18042", PI_GATEWAY_PORT: "19042", HOST_CWD: "/tmp" },
-        encoding: "utf8",
-      },
-    );
-    // Published host port == in-container listen port (no drift), dashboard.
-    expect(out).toMatch(/published:\s*"?18042"?/);
-    expect(out).toMatch(/target:\s*18042/);
-    // Container env DASHBOARD_PORT tracks the exported value.
-    expect(out).toMatch(/DASHBOARD_PORT:\s*"?18042"?/);
-    // Same for the gateway port — guards against the gateway env re-hardcoding.
-    expect(out).toMatch(/published:\s*"?19042"?/);
-    expect(out).toMatch(/target:\s*19042/);
-    expect(out).toMatch(/PI_GATEWAY_PORT:\s*"?19042"?/);
-  });
+  it(
+    "published port tracks listen port + container env",
+    () => {
+      const out = execFileSync(
+        "docker",
+        [
+          "compose",
+          "-f",
+          path.join(DOCKER_DIR, "compose.yml"),
+          "-f",
+          path.join(DOCKER_DIR, "compose.test.yml"),
+          "config",
+        ],
+        {
+          cwd: DOCKER_DIR,
+          env: { ...process.env, DASHBOARD_PORT: "18042", PI_GATEWAY_PORT: "19042", HOST_CWD: "/tmp" },
+          encoding: "utf8",
+          timeout: 60_000,
+        },
+      );
+      // Published host port == in-container listen port (no drift), dashboard.
+      expect(out).toMatch(/published:\s*"?18042"?/);
+      expect(out).toMatch(/target:\s*18042/);
+      // Container env DASHBOARD_PORT tracks the exported value.
+      expect(out).toMatch(/DASHBOARD_PORT:\s*"?18042"?/);
+      // Same for the gateway port — guards against the gateway env re-hardcoding.
+      expect(out).toMatch(/published:\s*"?19042"?/);
+      expect(out).toMatch(/target:\s*19042/);
+      expect(out).toMatch(/PI_GATEWAY_PORT:\s*"?19042"?/);
+    },
+    60_000,
+  );
 });
 
 if (!hasDocker()) {