diff --git a/sdk/build.mjs b/sdk/build.mjs
index 5ed9fe4..3583922 100644
--- a/sdk/build.mjs
+++ b/sdk/build.mjs
@@ -2,5 +2,5 @@ import { build } from "esbuild";
 await build({
   entryPoints: ["src/index.ts"],
   bundle: true, minify: true, format: "iife",
-  outfile: "dist/v1.js", target: ["es2018"],
+  outfile: "dist/v1.js", target: ["es2020"], // 代码依赖 globalThis（es2018 目标名不副实）
 });
diff --git a/sdk/src/events.ts b/sdk/src/events.ts
index 06936af..f681472 100644
--- a/sdk/src/events.ts
+++ b/sdk/src/events.ts
@@ -10,7 +10,11 @@ export function startPageTracking(t: Transport) {
   let activeMs = 0;
   let lastAct = Date.now();
   const act = () => {
-    lastAct = Date.now();
+    try {
+      lastAct = Date.now();
+    } catch {
+      /* 静默（spec §4.5 红线：监听器异常不得冒泡到宿主页） */
+    }
   };
   ["pointerdown", "keydown", "wheel", "touchstart"].forEach((e) =>
     document.addEventListener(e, act, { passive: true, capture: true })
@@ -59,7 +63,11 @@ export function startPageTracking(t: Transport) {
     }
   };
   document.addEventListener("visibilitychange", () => {
-    if (document.hidden) close();
+    try {
+      if (document.hidden) close();
+    } catch {
+      /* 静默：document.hidden 读取本身也不得冒泡异常（close 内部已自包） */
+    }
   });
   window.addEventListener("pagehide", close);
 }
diff --git a/sdk/src/index.ts b/sdk/src/index.ts
index 84efd7a..e142d60 100644
--- a/sdk/src/index.ts
+++ b/sdk/src/index.ts
@@ -49,6 +49,19 @@ function dispatch(cmd: string, arg?: unknown) {
   }
 }
 
-// 必须先替换全局入口再重放队列：重放期间宿主新调用直接进 dispatch，不再排队
+// 必须先替换全局入口再重放队列：重放期间宿主新调用直接进 dispatch，不再排队。
+// 宿主队列数据不可信（非可迭代项等）——模块顶层也不得抛（spec §4.5 唯一未保护路径）；
+// 单个坏条目只跳过自身，不吞掉后续排队的 init/track
 g.ctk = dispatch;
-q.forEach(([c, a]) => dispatch(c, a));
+try {
+  q.forEach((entry) => {
+    try {
+      const [c, a] = entry as Cmd;
+      dispatch(c, a);
+    } catch {
+      /* 静默：坏条目跳过，继续重放 */
+    }
+  });
+} catch {
+  /* 静默：q 本身不可迭代/无 forEach——放弃重放，入口已接管 */
+}
diff --git a/sdk/src/transport.ts b/sdk/src/transport.ts
index 113bc66..710c0cb 100644
--- a/sdk/src/transport.ts
+++ b/sdk/src/transport.ts
@@ -49,10 +49,12 @@ export class Transport {
         events,
       });
       if (beacon && navigator.sendBeacon) {
-        navigator.sendBeacon(
+        // 返回 false＝浏览器拒收（队列满/载荷超 64KB 等）→ 整批丢，须计 dropped
+        const ok = navigator.sendBeacon(
           this.cfg.endpoint,
           new Blob([body], { type: "text/plain" })
         );
+        if (!ok) this.dropped += n;
         return;
       }
       this.send(body, events.length);
diff --git a/sdk/test/events.test.ts b/sdk/test/events.test.ts
index d441b26..623e615 100644
--- a/sdk/test/events.test.ts
+++ b/sdk/test/events.test.ts
@@ -118,6 +118,21 @@ describe("events / startPageTracking", () => {
     expect(fetchMock).not.toHaveBeenCalled();
   });
 
+  it("30s 无活动不累计：单次活动后空闲 35s → active_ms 恰为 29000 后停止", async () => {
+    window.history.pushState({}, "", "/pidle");
+    const t = mkTransport("site-idle");
+    startPageTracking(t);
+    document.dispatchEvent(new Event("pointerdown")); // 仅此一次活动
+    await vi.advanceTimersByTimeAsync(35_000);
+
+    window.dispatchEvent(new Event("pagehide"));
+    const bodies = await beaconBodies("site-idle");
+    expect(bodies).toHaveLength(1);
+    const stay = bodies[0].events.find((e) => e.event_name === "page_stay")!;
+    // tick 于 +1s..+29s 时 Date.now()-lastAct<30000 成立（+30s 起等于 30000 不成立）
+    expect(stay.properties.active_ms).toBe(29000);
+  });
+
   it("隐藏→恢复→再隐藏：两段 stay 各自正确（第二段从 0 重新累计）", async () => {
     window.history.pushState({}, "", "/p6");
     const t = mkTransport("site-t6");
diff --git a/sdk/test/transport.test.ts b/sdk/test/transport.test.ts
index 689574c..5356ff7 100644
--- a/sdk/test/transport.test.ts
+++ b/sdk/test/transport.test.ts
@@ -177,6 +177,16 @@ describe("transport", () => {
     expect(t.dropped).toBe(1); // maxRetry=0 耗尽 → 按事件数丢弃
   });
 
+  it("sendBeacon 返回 false（队列满/载荷超限）按本批事件数计 dropped", () => {
+    vi.stubGlobal("navigator", { sendBeacon: vi.fn().mockReturnValue(false) });
+    const t = new Transport(mkCfg({ batchSize: 10 }));
+    t.push({ event_id: "e1" });
+    t.push({ event_id: "e2" });
+    t.flush(true);
+    expect(t.dropped).toBe(2); // 信标被浏览器拒收（64KB 上限等）→ 整批丢
+    expect(fetchMock).not.toHaveBeenCalled();
+  });
+
   it("stringify 抛错（track 引入宿主可控对象）：已换出批次按事件数计 dropped", () => {
     const t = new Transport(mkCfg({ batchSize: 10, flushMs: 60000 }));
     const bad: { event_id: string; self?: unknown } = { event_id: "bad" };