diff --git a/docs/BUG_HISTORY.md b/docs/BUG_HISTORY.md
index 82a74fe5..a8e603c5 100644
--- a/docs/BUG_HISTORY.md
+++ b/docs/BUG_HISTORY.md
@@ -3348,3 +3348,18 @@
 - 防复发：资料完整性、Case 可创建性和是否可以立即执行分钟级扫描必须分层；宽范围应先通过事件问题逐步缩小，不得以 `profile_incomplete` 阻止用户进入，也不得生成虚假具体出生时间。
 - 相关记录：BUG-127、BUG-196、BUG-197
 - 修复版本：本次 staging 修复提交（精确 SHA 以远端分支与 staging health 验收结果为准）
+
+## BUG-199 | Case 创建把可解析的空时区偏移误判为出生资料不完整
+
+- 状态：resolved（本地候选，待 staging 发布与登录态业务验收）
+- 首次发现：2026-08-15
+- 最近更新：2026-08-15
+- 影响面：`/api/rectification/cases/open`、保存了 IANA 时区但 `timezone_offset` 为空的全球出生地点资料，尤其是 `period_only` / `unknown` 用户。
+- 用户现象：用户已选择“晚上”等合法出生时段，页面也认为出生资料完整，但开始生时校正仍返回 HTTP 422 `profile_incomplete`。
+- 触发条件：Profile 已有出生日期、地点标签、坐标、`timezone_id` 和合法时间声明，但缓存字段 `timezone_offset` 为 `null`。
+- 根因：资料表单和账户保存合同允许用 IANA `timezone_id` 表达完整地点，既有普通咨询与 Journey 链路也会按出生日期和参考时间动态解析历史 offset；V9 Case 服务却在调用同一解析器之前直接强制 `timezone_offset !== null`，把可恢复的派生字段缺失误判成用户资料缺失。
+- 修复：V9 Profile 读取后先调用共享 `resolveMissingBirthTimezoneOffset`；具体时间使用填报分钟，时段声明使用服务器定义的时段参考时刻，未知时间使用中午参考时刻，只用于解析该日期的历史 UTC offset，不会生成或确认具体出生分钟。解析成功后再执行原有完整性和候选范围校验；解析服务异常映射为 `profile_unavailable`，不再冒充 `profile_incomplete`。
+- 验证：新增真实服务边界回归，先证明 `period_only + evening + timezone_id + timezone_offset null` 在 RPC 前稳定抛出 `profile_incomplete`，修复后确认调用历史时区接口、候选范围仍为 `18:00–22:59`、baseline 使用解析得到的 offset 并成功创建 Case。聚焦测试、Lint、TypeScript、远端 SHA 与 staging 业务结果按本次发布记录补充。
+- 防复发：IANA 时区是地点真相，`timezone_offset` 是依赖出生日期与参考时刻的派生值；所有需要 offset 的服务必须先走共享解析边界，再区分真正资料不完整与下游服务异常。
+- 相关记录：BUG-127、BUG-198
+- 修复版本：本次 staging 修复提交（精确 SHA 以远端分支与 staging health 验收结果为准）
diff --git a/frontend/src/lib/rectification-agentic/v9/case-service.ts b/frontend/src/lib/rectification-agentic/v9/case-service.ts
index d56e5b18..c2161e38 100644
--- a/frontend/src/lib/rectification-agentic/v9/case-service.ts
+++ b/frontend/src/lib/rectification-agentic/v9/case-service.ts
@@ -8,6 +8,7 @@
  */
 import { createHash } from "node:crypto";
 import type { SupabaseClient } from "@supabase/supabase-js";
+import { resolveMissingBirthTimezoneOffset } from "../../birth-profile-timezone.ts";
 import { normalizePersistedBirthDate } from "../../birth-time-intake-model.ts";
 import {
   resolveActiveSkillPackage,
@@ -180,7 +181,13 @@ export async function loadV9RectificationProfile(
     .single();
   if (error || !data) throw new RectificationCaseServiceError("profile_unavailable");
 
-  const row = data as Record<string, unknown>;
+  let resolvedData: unknown;
+  try {
+    resolvedData = await resolveMissingBirthTimezoneOffset(data);
+  } catch {
+    throw new RectificationCaseServiceError("profile_unavailable");
+  }
+  const row = resolvedData as Record<string, unknown>;
   const birthDate = normalizePersistedBirthDate(row.birth_date);
   const latitude = numberOrNull(row.latitude);
   const longitude = numberOrNull(row.longitude);
diff --git a/frontend/tests/rectification-v9-case-service.test.ts b/frontend/tests/rectification-v9-case-service.test.ts
index 821b7053..b88f0b85 100644
--- a/frontend/tests/rectification-v9-case-service.test.ts
+++ b/frontend/tests/rectification-v9-case-service.test.ts
@@ -168,6 +168,68 @@ test("period-only profiles open with their selected server-owned range", async (
   }
 });
 
+test("period-only profiles with an IANA timezone can open when the cached offset is missing", async () => {
+  const originalFetch = globalThis.fetch;
+  const capturedArgs: { value: Record<string, unknown> | null } = { value: null };
+  let timezoneLookupCalled = false;
+  globalThis.fetch = async (input, init) => {
+    timezoneLookupCalled = true;
+    assert.equal(String(input), "http://127.0.0.1:5200/api/location/timezone");
+    assert.deepEqual(JSON.parse(String(init?.body)), {
+      latitude: 36.420487,
+      longitude: 114.209936,
+      birthDate: "1997-08-08",
+      birthTime: "20:30",
+    });
+    return new Response(JSON.stringify({
+      available: true,
+      timezoneId: "Asia/Shanghai",
+      timezoneOffset: 8,
+    }), { status: 200 });
+  };
+
+  try {
+    const accounting = fakeAccounting({
+      profile: {
+        ...completeProfile,
+        reported_birth_time: null,
+        birth_time_source: "period_only",
+        birth_time_period: "evening",
+        timezone_offset: null,
+      },
+      rpc: async (_fn, args) => {
+        capturedArgs.value = args;
+        return {
+          data: {
+            disposition: "created",
+            case_id: caseId,
+            session_id: sessionId,
+            status: "draft",
+            should_start_opening: true,
+            skill_version: "9.0.0",
+          },
+          error: null,
+        };
+      },
+    });
+
+    const response = await openRectificationCase(accounting, "user-1", {
+      intent: "homepage",
+      requestId,
+    });
+
+    assert.equal(response.disposition, "created");
+    assert.equal(timezoneLookupCalled, true);
+    assert.deepEqual(capturedArgs.value?.p_candidate_range, { start_time: "18:00", end_time: "22:59" });
+    assert.equal(
+      (capturedArgs.value?.p_baseline_birth_snapshot as Record<string, unknown>).timezone_offset,
+      8,
+    );
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
 test("unknown-time profiles open with a full-day server-owned range", async () => {
   const capturedArgs: { value: Record<string, unknown> | null } = { value: null };
   const accounting = fakeAccounting({