diff --git a/docs/project-memory/plans/【里程碑】游戏分发目录详情与在线游玩-2026-09-18.md b/docs/project-memory/plans/【里程碑】游戏分发目录详情与在线游玩-2026-09-18.md
index ee5282303..f4db3314a 100644
--- a/docs/project-memory/plans/【里程碑】游戏分发目录详情与在线游玩-2026-09-18.md
+++ b/docs/project-memory/plans/【里程碑】游戏分发目录详情与在线游玩-2026-09-18.md
@@ -51,7 +51,7 @@
 - [x] 登录用户创建服务端分配的游戏，owner 不能由请求伪造；其他账号不能读取私有版本、上传、提交或撤销。
 - [x] 服务端接收真实 ZIP 字节，重算摘要/字节数并建立展开清单；只有 metadata 的请求不能获得已上传或已发布状态。
 - [x] 缺入口、越界/重复/大小写冲突路径、符号链接、压缩炸弹、敏感内容和额度超限均失败关闭，原私有对象和公开状态保持一致。
-- [ ] 一份版本只接受一份已确认内容；同 key 同请求重放无重复游戏/版本，不同请求冲突；同版本并发上传不混写。
+- [x] 一份版本只接受一份已确认内容；同 key 同请求重放无重复游戏/版本，不同请求冲突；同版本并发上传不混写。
 - [ ] 校验可异步恢复，响应丢失、服务进程退出和客户端重试均回到原版本；确定失败和未知结果在响应中可区分。
 - [ ] 正常及失败状态、私有查询和错误 envelope 在 Rust 与 TypeScript DTO 中一致；新增 schema、迁移、表目录与绑定一致。
 
@@ -163,7 +163,9 @@
   - **本轮新增** `scripts/check-game-distribution-owner-isolation.mjs`（`npm run check:game-distribution-owner-isolation`）：对本地真实栈（SpacetimeDB `xushi-p4wfr` @ 127.0.0.1:3101 + api-server @ 127.0.0.1:4198，发布灰度按既有 E2E 口径临时开启后恢复关闭）注册两个真实账号，作者建游戏与版本后逐条验证越权：读私有版本 404、读上传状态 404、写分片 404、确认分包 404、送审 404、撤回 404、未认证读取 401；越权写之后作者侧 `receivedBytes` 仍为 0（越权请求没有落任何副作用）；请求体里塞 `ownerUserId` / `owner_user_id` 的伪造游戏仍只出现在请求者自己的 `my-games`、不出现在被冒名账号的 `my-games`；作者撤回自己的版本得到 `cancelled`。**21 项全部 PASS**。
   - **本轮顺带修掉一处真实缺陷**：`submit_version` 之前直接调 `get_owner_game_distribution_version`，owner 不匹配被映射成 403，而读版本/上传状态/分片/确认/撤回都按 404 处理——同一条「不属于当前主体」的语义出现两种错误码，送审入口会泄露版本是否存在。改成复用 `load_owner_version_or_404` 后，他人送审作者版本与送审不存在的版本都返回 404；脚本里这两条断言分别覆盖，修复前前者是 403 `FORBIDDEN` 让用例变红。
   - 边界：脚本会为「建游戏必须提供封面」写一个 67 字节 PNG 到 dev bucket（走现役直传 + 确认链路）；发行包分片与确认全部停在越权拒绝之前，不产生任何对象。
+- 已勾选（第 4 条：一份版本只接受一份已确认内容、同 key 重放不产生第二份、换请求体冲突、同版本并发上传不混写）——本轮补齐
+  - 领域层原有 `idempotency_replays_same_snapshot_and_rejects_digest_conflict`、`validation_failure_can_retry_same_confirmed_package`、`a_version_accepts_only_one_confirmed_package`；**本轮新增** `scripts/check-game-distribution-upload-concurrency.mjs`（`npm run check:game-distribution-upload-concurrency`）在本地真实栈补接口层：同 key 同请求重放建游戏/建版本返回同一条记录、同 key 换请求体建游戏 409 `CONFLICT`、同版本同偏移并发写两片相同字节只成功一片、服务端权威已收字节等于单份包长（没有重复追加）、随后确认校验通过并落到 `uploaded`（重复追加或混写都会让校验失败）、换 key 第二次送审 409 且版本数仍为 1。**17 项全部 PASS**。
+  - **本轮顺带修掉并发落败请求的错误码**：分片追加失败时之前直接把 OSS 的 position 冲突映射成 `502 UPSTREAM_ERROR`；现在追加失败后回读权威已收字节，只要长度已前进就返回 409 `PACKAGE_UPLOAD_OFFSET_MISMATCH` 并带上 `receivedBytes`，客户端可直接按权威偏移续传。修复前脚本观察到 `502/UPSTREAM_ERROR`，修复后同一条断言看到 `409/PACKAGE_UPLOAD_OFFSET_MISMATCH receivedBytes=751`。
 - 仍未勾选（缺口写具体，避免"看起来做了"）
-  - 第 4 条（一份版本只接受一份已确认内容；同 key 同请求幂等、不同请求冲突；同版本并发上传不混写）：前两半已覆盖——`idempotency_replays_same_snapshot_and_rejects_digest_conflict`、`validation_failure_can_retry_same_confirmed_package`、api-server 的 `idempotency_key_requires_a_bounded_non_empty_header`；**本轮新增** `a_version_accepts_only_one_confirmed_package`（不同摘要或字节数的确认被拒为 `PackageMismatch`，重复确认同一份内容返回同一包身份；变异去掉该守卫后只有它变红）。**仍缺**「同版本并发上传不混写」：串行化在 `spacetime-module` / api-server 的 CAS 那一层，领域服务本身是同步的，需要在那一层写用例。
-  - 第 5 条（校验可异步恢复；响应丢失、服务进程退出与客户端重试回到原版本；确定失败与未知结果可区分）：只有 api-server 的 `recovery_action_covers_every_version_status` 覆盖"状态 → 恢复动作"的映射；后两句在 game-distribution 链路没有用例。
+  - 第 5 条（校验可异步恢复；响应丢失、服务进程退出和客户端重试回到原版本；确定失败和未知结果可区分）：`recovery_action_covers_every_version_status` 覆盖状态到恢复动作的映射；**本轮补齐「客户端重试」**——`check:game-distribution-upload-concurrency` 里同 key 重放送审得到 `202 replayed=true` 且仍是同一个版本、换 key 重复送审 409 且不产生第二份提交。**仍缺**「响应丢失与 api-server 进程退出后回到原版本」：需要在 8 MiB 分片上传中途重启 api-server 再续传的编排用例，本轮未做。
   - 第 6 条（状态/私有查询/错误 envelope 的 Rust 与 TS DTO 一致；新增 schema、迁移、表目录与绑定一致）：后半句有门禁（`npm run lint` 内的 SpacetimeDB schema guard 覆盖 85 张表、生成绑定校验通过）。**本轮新增** `check:game-distribution-dto-parity`（已接进 `npm run lint`）：按显式映射表逐字段/逐变体比对 14 组 Rust `shared-contracts` DTO 与手写 `packages/shared/src/contracts/gameDistribution.ts`，两个方向都做过变异验证——TS 侧把 `name` 改成 `displayName`、Rust 侧给 `GameDistributionAuthor` 加 `extra_field`，各自都让门禁失败并指出缺哪个字段；脚本同时登记了 7 个「服务端逐字段手拼 JSON、没有 Rust 结构体」的 TS 类型。**本轮补齐** `coverObjectKey` / `screenshots` / `publicationRevision` 四个字段进 Rust 结构体（依据是 `game_payload` 与 `private_version_payload` 实际发出的键），并删掉脚本里用来豁免它们的 `TS_ONLY_FIELDS` 白名单：现在任一方向多出字段都会让门禁失败，作者侧响应省略 `currentVersion` 这一条差异改用 TS 可选字段描述。**本轮再补构建器一层**：门禁新增 `RESPONSE_BUILDERS`，解析 `server-rs/crates/api-server/src/modules/game_distribution.rs` 里 `game_payload` / `public_game_payload` / `private_version_payload` / `version_summary_payload` 的 `json!` 顶层键与顶层 `object.insert(…)`，逐键比对 TS 类型：发出的键必须都在类型里、类型的必需字段必须都发出、`public_game_payload` 还必须发出被 TS 标成可选的 `currentVersion`，`game_payload` 的 `author` / `deviceSupport` 两个嵌套字面量同样逐键比对。变异验证五种改法各自让门禁失败并指出具体键：删掉 `game_payload.publicationRevision`、删掉 `deviceSupport.touch`、把 `author.avatarUrl` 改名、把插入的 `currentVersion` 改名、给 `version_summary_payload` 加一个 TS 没有的键；恢复后通过。**剩余缺口**：门禁比对的是键而不是值的类型，也覆盖不到未登记的嵌套对象与 envelope——成功/失败 envelope 的字段由 TS 侧运行时守卫（`packages/shared/src/http.ts`、`src/services/apiClient.ts`）消费，要彻底类型化得先把这两个响应改成结构化构建。
diff --git a/package.json b/package.json
index ad3a7cbe7..52699419b 100644
--- a/package.json
+++ b/package.json
@@ -75,6 +75,7 @@
     "check:game-distribution-dto-parity": "node scripts/check-game-distribution-dto-parity.mjs",
     "check:game-distribution-media-e2e": "node scripts/check-game-distribution-media-e2e.mjs",
     "check:game-distribution-owner-isolation": "node scripts/check-game-distribution-owner-isolation.mjs",
+    "check:game-distribution-upload-concurrency": "node scripts/check-game-distribution-upload-concurrency.mjs",
     "check:production-ops": "node scripts/check-production-ops-guardrails.mjs",
     "check:preview-deployer": "node scripts/check-preview-deployer.mjs",
     "check:maintenance-page": "node scripts/check-maintenance-page.mjs",
diff --git a/scripts/check-game-distribution-upload-concurrency.mjs b/scripts/check-game-distribution-upload-concurrency.mjs
new file mode 100644
index 000000000..d2d234a5e
--- /dev/null
+++ b/scripts/check-game-distribution-upload-concurrency.mjs
@@ -0,0 +1,441 @@
+// 游戏分发「同版本并发上传不混写 + 幂等重放」真实链路检查（需要本地 dev 栈：SpacetimeDB + api-server）。
+//
+// 用法：
+//   E2E_ADMIN_USER=<管理员用户名> E2E_ADMIN_PASSWORD=<管理员密码> \
+//     npm run check:game-distribution-upload-concurrency
+//   E2E_API_BASE 可覆盖 api-server 地址（默认 http://127.0.0.1:4198）。
+//
+// 覆盖：
+//   1. 同一个 Idempotency-Key 重放建游戏 / 建版本 → 返回同一条记录，不产生第二份；
+//      同一个 Key 换请求体 → 冲突拒绝。
+//   2. 同一个版本、同一个偏移量并发写两片相同字节 → 只有一片被接受，另一片是可重试错误；
+//      已收字节等于单份包长，随后的确认校验必须通过（混写或重复追加都会让校验失败）。
+//   3. 送审成功后用同一个 Key 重放 → 202 `replayed=true` 且仍是同一版本；
+//      不同 Key 重复送审不会产生第二份提交（版本数仍为 1、状态不变）。
+// 整条链路只在本地 dev 数据库与该 dev bucket 的对象前缀下落行；一个几百字节的发行包对象
+// 会在确认后留在 bucket 里（与现役上传链路的产物一致），另有 67 字节封面 PNG。
+import { createHash } from 'node:crypto';
+
+import JSZip from 'jszip';
+
+const COVER_PNG = Buffer.from(
+  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==',
+  'base64',
+);
+const API = process.env.E2E_API_BASE ?? 'http://127.0.0.1:4198';
+const ENVELOPE = { 'x-genarrative-response-envelope': 'v1' };
+const ADMIN_USER = (process.env.E2E_ADMIN_USER ?? '').trim();
+const ADMIN_PASSWORD = process.env.E2E_ADMIN_PASSWORD ?? '';
+const DEV_PASSWORD = 'GenE2e123!';
+
+if (!ADMIN_USER || !ADMIN_PASSWORD) {
+  console.error(
+    '缺少 E2E_ADMIN_USER / E2E_ADMIN_PASSWORD：本脚本要按发布灰度口径打开 ' +
+      'game-distribution:publish 写入口；本地栈可先以 GENARRATIVE_ADMIN_USERNAME / ' +
+      'GENARRATIVE_ADMIN_PASSWORD 启动 api-server。',
+  );
+  process.exit(2);
+}
+
+let failures = 0;
+function check(name, ok, detail = '') {
+  if (!ok) failures += 1;
+  console.log(
+    `${ok ? 'PASS' : 'FAIL'}  ${name}${detail ? ` :: ${detail}` : ''}`,
+  );
+}
+
+async function api(path, options = {}) {
+  const { method = 'GET', token, body, headers = {}, binary } = options;
+  const finalHeaders = { ...ENVELOPE, ...headers };
+  if (token) finalHeaders.Authorization = `Bearer ${token}`;
+  let finalBody;
+  if (binary) {
+    finalBody = binary;
+  } else if (body !== undefined) {
+    finalHeaders['Content-Type'] = 'application/json';
+    finalBody = JSON.stringify(body);
+  }
+  const response = await fetch(`${API}${path}`, {
+    method,
+    headers: finalHeaders,
+    body: finalBody,
+  });
+  const text = await response.text();
+  let json = null;
+  try {
+    json = JSON.parse(text);
+  } catch {
+    json = null;
+  }
+  return {
+    status: response.status,
+    json,
+    text,
+    data: json?.data,
+    error: json?.error,
+  };
+}
+
+// 两份内容不同但长度一致的条目，保证 fixture ZIP 的可复现长度（分片并发用例需要固定声明大小）。
+async function buildFixtureZip() {
+  const archive = new JSZip();
+  archive.file('index.html', '<!doctype html><title>concurrency</title>');
+  archive.file('assets/app.js', `console.log('${'x'.repeat(384)}');`);
+  const bytes = await archive.generateAsync({ type: 'uint8array' });
+  return Buffer.from(bytes);
+}
+
+function gameMetadata(title) {
+  return {
+    title,
+    summary: '并发上传与幂等重放用例的临时游戏',
+    description: '',
+    category: '休闲',
+    tags: ['e2e'],
+    deviceSupport: { desktop: true, mobile: false, touch: false },
+    inputModes: ['keyboard', 'mouse'],
+    orientation: 'landscape',
+  };
+}
+
+async function uploadCover(token, id) {
+  const fileName = `upload-safety-${id}.png`;
+  const ticket = await api('/api/assets/direct-upload-tickets', {
+    method: 'POST',
+    token,
+    body: {
+      legacyPrefix: 'generated-character-drafts',
+      pathSegments: ['game-distribution', 'upload-safety', String(id)],
+      fileName,
+      contentType: 'image/png',
+      access: 'private',
+      maxSizeBytes: COVER_PNG.length,
+      metadata: { asset_kind: 'game_distribution_cover' },
+    },
+  });
+  if (ticket.status !== 200) {
+    throw new Error(
+      `创建直传凭证失败 ${ticket.status} ${ticket.text.slice(0, 300)}`,
+    );
+  }
+  const upload = ticket.data.upload;
+  const form = new FormData();
+  for (const [key, value] of Object.entries(upload.formFields ?? {})) {
+    if (value !== null && value !== undefined) form.append(key, String(value));
+  }
+  form.append('file', new Blob([COVER_PNG], { type: 'image/png' }), fileName);
+  const put = await fetch(upload.host, { method: 'POST', body: form });
+  if (!put.ok) {
+    throw new Error(`直传对象存储失败 ${put.status}`);
+  }
+  const confirm = await api('/api/assets/objects/confirm', {
+    method: 'POST',
+    token,
+    body: {
+      bucket: upload.bucket,
+      objectKey: upload.objectKey,
+      contentType: 'image/png',
+      contentLength: COVER_PNG.length,
+      assetKind: 'game_distribution_cover',
+      accessPolicy: 'private',
+      entityId: 'game-distribution-upload-safety',
+    },
+  });
+  if (confirm.status !== 200) {
+    throw new Error(
+      `确认素材失败 ${confirm.status} ${confirm.text.slice(0, 300)}`,
+    );
+  }
+  return confirm.data.assetObject.assetObjectId;
+}
+
+async function main() {
+  const adminLogin = await api('/admin/api/login', {
+    method: 'POST',
+    body: { username: ADMIN_USER, password: ADMIN_PASSWORD },
+  });
+  const admin = adminLogin.data?.token ?? adminLogin.data?.accessToken;
+  check(
+    '管理员登录成功',
+    adminLogin.status === 200 && Boolean(admin),
+    `status=${adminLogin.status}`,
+  );
+  if (!admin) process.exit(1);
+
+  const stamp = Date.now();
+  const register = await api('/api/auth/entry', {
+    method: 'POST',
+    body: {
+      purePhoneNumber: `139${String(stamp).slice(-8)}`,
+      password: DEV_PASSWORD,
+    },
+  });
+  const author = register.data?.token;
+  check(
+    '作者注册拿到 token',
+    register.status === 200 && Boolean(author),
+    `status=${register.status}`,
+  );
+  if (!author) process.exit(1);
+
+  const setGate = (enabled, rolloutPercent) =>
+    api('/admin/api/feature-gates', {
+      method: 'PUT',
+      token: admin,
+      body: {
+        gateKey: 'game-distribution:publish',
+        enabled,
+        rolloutPercent,
+        allowUserIds: [],
+        allowUserTags: [],
+        denyUserIds: [],
+        description: 'E2E 并发上传与幂等重放',
+      },
+    });
+  const gateOpen = await setGate(true, 100);
+  check(
+    '发布灰度可开启并放量',
+    gateOpen.status === 200,
+    `status=${gateOpen.status}`,
+  );
+
+  const zipBytes = await buildFixtureZip();
+  const zipSha256 = createHash('sha256').update(zipBytes).digest('hex');
+  const coverAssetId = await uploadCover(author, stamp);
+  const title = `并发上传 ${String(stamp).slice(-6)}`;
+  const metadata = { ...gameMetadata(title), coverAssetId };
+
+  // 1. 幂等重放：同 key 同请求返回同一条记录，同 key 换请求体冲突。
+  const gameKey = `safety-game-${stamp}`;
+  const created = await api('/api/game-distribution/games', {
+    method: 'POST',
+    token: author,
+    headers: { 'Idempotency-Key': gameKey },
+    body: metadata,
+  });
+  const gameId = created.data?.id;
+  check(
+    '创建游戏成功',
+    created.status === 200 && Boolean(gameId),
+    `status=${created.status} msg=${created.error?.message ?? ''}`,
+  );
+  if (!gameId) process.exit(1);
+
+  const replayedGame = await api('/api/game-distribution/games', {
+    method: 'POST',
+    token: author,
+    headers: { 'Idempotency-Key': gameKey },
+    body: metadata,
+  });
+  check(
+    '同 key 同请求重放建游戏返回同一 game',
+    replayedGame.status === 200 && replayedGame.data?.id === gameId,
+    `status=${replayedGame.status} gameId=${replayedGame.data?.id ?? ''}`,
+  );
+
+  const conflictingGame = await api('/api/game-distribution/games', {
+    method: 'POST',
+    token: author,
+    headers: { 'Idempotency-Key': gameKey },
+    body: { ...metadata, title: `${title} 改` },
+  });
+  check(
+    '同 key 换请求体建游戏被拒（不产生第二份）',
+    conflictingGame.status === 409,
+    `status=${conflictingGame.status} code=${conflictingGame.error?.code ?? ''}`,
+  );
+
+  const versionKey = `safety-version-${stamp}`;
+  const versionBody = {
+    packageSha256: zipSha256,
+    packageBytes: zipBytes.length,
+    packageFileCount: 2,
+    packageEntryPath: 'index.html',
+    gameMetadata: metadata,
+  };
+  const versionResponse = await api(
+    `/api/game-distribution/games/${gameId}/versions`,
+    {
+      method: 'POST',
+      token: author,
+      headers: { 'Idempotency-Key': versionKey },
+      body: versionBody,
+    },
+  );
+  const versionId = versionResponse.data?.versionId;
+  const publicationRevision = versionResponse.data?.publicationRevision ?? 0;
+  check(
+    '创建版本成功（awaiting_upload）',
+    versionResponse.status === 200 &&
+      Boolean(versionId) &&
+      versionResponse.data?.status === 'awaiting_upload',
+    `status=${versionResponse.status} versionStatus=${versionResponse.data?.status}`,
+  );
+  if (!versionId) process.exit(1);
+
+  const replayedVersion = await api(
+    `/api/game-distribution/games/${gameId}/versions`,
+    {
+      method: 'POST',
+      token: author,
+      headers: { 'Idempotency-Key': versionKey },
+      body: versionBody,
+    },
+  );
+  check(
+    '同 key 同请求重放建版本返回同一 version',
+    replayedVersion.status === 200 &&
+      replayedVersion.data?.versionId === versionId,
+    `status=${replayedVersion.status} versionId=${replayedVersion.data?.versionId ?? ''}`,
+  );
+
+  // 2. 同版本同偏移并发写两片：只允许一片落地。
+  const chunk = (idempotencyKey) =>
+    api(`/api/game-distribution/versions/${versionId}/package/chunk`, {
+      method: 'PUT',
+      token: author,
+      headers: {
+        'Content-Type': 'application/octet-stream',
+        'Idempotency-Key': idempotencyKey,
+        'x-genarrative-upload-offset': '0',
+      },
+      binary: zipBytes,
+    });
+  const raced = await Promise.all([
+    chunk(`safety-chunk-a-${stamp}`),
+    chunk(`safety-chunk-b-${stamp}`),
+  ]);
+  const winners = raced.filter((item) => item.status === 200);
+  const losers = raced.filter((item) => item.status !== 200);
+  check(
+    '并发同偏移分片只有一片写入成功',
+    winners.length === 1,
+    raced
+      .map(
+        (item) =>
+          `${item.status}${item.error?.code ? `/${item.error.code}` : ''}`,
+      )
+      .join(' '),
+  );
+  check(
+    '落败请求返回偏移冲突与权威已收字节（可直接续传）',
+    losers.length === 1 &&
+      losers[0].status === 409 &&
+      losers[0].error?.details?.receivedBytes === zipBytes.length,
+    losers
+      .map(
+        (item) =>
+          `${item.status} ${item.error?.code ?? ''} receivedBytes=${item.error?.details?.receivedBytes ?? 'n/a'}`,
+      )
+      .join(''),
+  );
+  check(
+    '成功分片回报的已收字节等于单份包长',
+    winners[0]?.data?.receivedBytes === zipBytes.length,
+    `receivedBytes=${winners[0]?.data?.receivedBytes ?? 'n/a'} zip=${zipBytes.length}`,
+  );
+
+  const stateAfterRace = await api(
+    `/api/game-distribution/versions/${versionId}/package/upload-state`,
+    { token: author },
+  );
+  check(
+    '服务端权威已收字节等于单份包长（没有重复追加）',
+    stateAfterRace.status === 200 &&
+      stateAfterRace.data?.receivedBytes === zipBytes.length,
+    `receivedBytes=${stateAfterRace.data?.receivedBytes ?? 'n/a'}`,
+  );
+
+  const completed = await api(
+    `/api/game-distribution/versions/${versionId}/package/complete`,
+    {
+      method: 'POST',
+      token: author,
+      headers: { 'Idempotency-Key': `safety-complete-${stamp}` },
+    },
+  );
+  check(
+    '并发落地的对象就是完整一份（确认校验通过并落到 uploaded）',
+    completed.status === 200 && completed.data?.status === 'uploaded',
+    `status=${completed.status} versionStatus=${completed.data?.status ?? ''} msg=${completed.error?.message ?? ''}`,
+  );
+
+  // 3. 送审与重放。
+  const submitKey = `safety-submit-${stamp}`;
+  const submitBody = { expectedPublicationRevision: publicationRevision };
+  const submitted = await api(
+    `/api/game-distribution/versions/${versionId}/submit`,
+    {
+      method: 'POST',
+      token: author,
+      headers: { 'Idempotency-Key': submitKey },
+      body: submitBody,
+    },
+  );
+  check(
+    '送审成功（202 + pending_review）',
+    submitted.status === 202 &&
+      submitted.data?.version?.status === 'pending_review',
+    `status=${submitted.status} versionStatus=${submitted.data?.version?.status ?? ''}`,
+  );
+
+  const replayedSubmit = await api(
+    `/api/game-distribution/versions/${versionId}/submit`,
+    {
+      method: 'POST',
+      token: author,
+      headers: { 'Idempotency-Key': submitKey },
+      body: submitBody,
+    },
+  );
+  check(
+    '同 key 重放送审回到同一个版本且 replayed=true',
+    replayedSubmit.status === 202 &&
+      replayedSubmit.data?.replayed === true &&
+      replayedSubmit.data?.version?.versionId === versionId &&
+      replayedSubmit.data?.version?.status === 'pending_review',
+    `status=${replayedSubmit.status} replayed=${replayedSubmit.data?.replayed}`,
+  );
+
+  const resubmitted = await api(
+    `/api/game-distribution/versions/${versionId}/submit`,
+    {
+      method: 'POST',
+      token: author,
+      headers: { 'Idempotency-Key': `safety-submit-again-${stamp}` },
+      body: submitBody,
+    },
+  );
+  const myGamesAfterResubmit = await api('/api/game-distribution/my-games', {
+    token: author,
+  });
+  const gameAfterResubmit = Array.isArray(myGamesAfterResubmit.data?.games)
+    ? myGamesAfterResubmit.data.games.find((item) => item.id === gameId)
+    : null;
+  check(
+    '换 key 重复送审按状态冲突拒绝且不产生第二份提交（版本数仍为 1）',
+    resubmitted.status === 409 &&
+      gameAfterResubmit?.versions?.length === 1 &&
+      gameAfterResubmit.versions[0]?.versionId === versionId &&
+      gameAfterResubmit.versions[0]?.status === 'pending_review',
+    `submitStatus=${resubmitted.status} replayed=${resubmitted.data?.replayed} versions=${gameAfterResubmit?.versions?.length ?? 'n/a'}`,
+  );
+
+  const gateClosed = await setGate(false, 0);
+  check(
+    '发布灰度恢复关闭',
+    gateClosed.status === 200,
+    `status=${gateClosed.status}`,
+  );
+
+  console.log(`\n${failures === 0 ? '全部通过' : `${failures} 项失败`}`);
+  process.exit(failures === 0 ? 0 : 1);
+}
+
+main().catch((error) => {
+  console.error(
+    `[check:game-distribution-upload-concurrency] 运行失败：${error}`,
+  );
+  process.exit(1);
+});
diff --git a/server-rs/crates/api-server/src/modules/game_distribution.rs b/server-rs/crates/api-server/src/modules/game_distribution.rs
index 558f88c55..89f07cd59 100644
--- a/server-rs/crates/api-server/src/modules/game_distribution.rs
+++ b/server-rs/crates/api-server/src/modules/game_distribution.rs
@@ -925,11 +925,11 @@ async fn upload_package_chunk(
                 "receivedBytes": received_bytes,
             })));
     }
-    let appended = oss
+    let append_result = oss
         .append_internal_object_with_retry(
             state.editor_oss_http_client(),
             OssAppendInternalObjectRequest {
-                object_key,
+                object_key: object_key.clone(),
                 content_type: Some("application/zip".to_string()),
                 position: offset,
                 body: body.to_vec(),
@@ -937,8 +937,36 @@ async fn upload_package_chunk(
             GAME_DISTRIBUTION_OSS_PUT_MAX_ATTEMPTS,
             &GAME_DISTRIBUTION_OSS_PUT_RETRY_DELAYS_MS,
         )
-        .await
-        .map_err(|error| map_oss_error(error, "aliyun-oss"))?;
+        .await;
+    let appended = match append_result {
+        Ok(appended) => appended,
+        Err(error) => {
+            // 追加失败也可能是「同偏移的并发写入先赢了一片」：先读权威已收字节，
+            // 只要长度已经前进就按偏移冲突返回，让客户端按权威偏移续传，
+            // 而不是把一个可恢复的并发结果报成上游故障。
+            if let Ok(authoritative) = staged_package_bytes(&state, oss, &object_key).await
+                && authoritative > offset
+            {
+                warn!(
+                    request_id = ctx.request_id(),
+                    operation = "package_chunk_offset_lost_race",
+                    game_id = %version.game_id,
+                    version_id = %version_id,
+                    declared_offset = offset,
+                    received_bytes = authoritative,
+                    "并发写入已推进已收字节，按偏移冲突返回权威位置"
+                );
+                return Err(AppError::from_status(StatusCode::CONFLICT)
+                    .with_code("PACKAGE_UPLOAD_OFFSET_MISMATCH")
+                    .with_message("分片偏移与服务端已收字节不一致，请按权威偏移续传")
+                    .with_details(json!({
+                        "provider": "game-distribution",
+                        "receivedBytes": authoritative,
+                    })));
+            }
+            return Err(map_oss_error(error, "aliyun-oss"));
+        }
+    };
     info!(
         request_id = ctx.request_id(),
         operation = "package_chunk_stored",