diff --git a/apps/server/src/modules/acquisition-organize/services/acquisition.ts b/apps/server/src/modules/acquisition-organize/services/acquisition.ts
index edebcf38..d215091e 100644
--- a/apps/server/src/modules/acquisition-organize/services/acquisition.ts
+++ b/apps/server/src/modules/acquisition-organize/services/acquisition.ts
@@ -233,17 +233,24 @@ export async function createSlotsFromTemplates(
 
 /** 追踪中的订阅里没有自己收录版本的,逐个补建;返回是否建了 */
 async function backfillSubscriptionSlots(
-  exec: Exec,
+  db: AoDeps["ctx"]["db"],
   subs: readonly SubscriptionRow[],
   slots: readonly Pick<AcquisitionSlotRow, "subscription_id">[],
 ): Promise<boolean> {
   let made = 0;
   for (const s of subs)
-    if (s.media_entity_id && !slots.some((x) => x.subscription_id === s.id))
-      made += await ensureSubscriptionSlot(exec, s);
+    if (s.media_entity_id && !slots.some((x) => x.subscription_id === s.id)) made += await ensureSlotLocked(db, s);
   return made > 0;
 }
 
+/** 评估路径上补建:锁订阅行,免得并发的两次评估各建一个 */
+function ensureSlotLocked(db: AoDeps["ctx"]["db"], sub: SubscriptionRow): Promise<number> {
+  return db.transaction().execute(async (trx) => {
+    await trx.selectFrom("subscription").select("id").where("id", "=", sub.id).forUpdate().execute();
+    return ensureSubscriptionSlot(trx, sub);
+  });
+}
+
 /** 订阅没有收录策略模板时的隐式缺省收录版本:无硬条件,表单的质量预设 / 包含排除随后由订阅参数写入 */
 export const DEFAULT_SLOT_TEMPLATE: SlotTemplate = { name: "默认版本" };
 
@@ -377,7 +384,7 @@ async function reevaluate(c: Ctx, input: EvaluateInput): Promise<EvaluateOutcome
     sub = sid ? await db.selectFrom("subscription").selectAll().where("id", "=", sid).executeTakeFirst() : undefined;
   } else if (input.subscriptionId) {
     sub = await db.selectFrom("subscription").selectAll().where("id", "=", input.subscriptionId).executeTakeFirst();
-    if (sub && (TRACKING_SUB_STATUSES as readonly string[]).includes(sub.status)) await ensureSubscriptionSlot(db, sub);
+    if (sub && (TRACKING_SUB_STATUSES as readonly string[]).includes(sub.status)) await ensureSlotLocked(db, sub);
     if (sub)
       focus = await db
         .selectFrom("acquisition_slot")
diff --git a/apps/server/test/acquisition-organize/rules-api.test.ts b/apps/server/test/acquisition-organize/rules-api.test.ts
index 0bbb8b4b..940f253a 100644
--- a/apps/server/test/acquisition-organize/rules-api.test.ts
+++ b/apps/server/test/acquisition-organize/rules-api.test.ts
@@ -84,7 +84,8 @@ describe.skipIf(!hasPg)("规则 API(真实 PG)", () => {
     });
     expect(ok.body.data).toMatchObject({ revision: 2, softPreferences: { hdr: ["DV"] } });
     const list = await h.api("GET", `/acquisition-slots?mediaEntityId=${e}`);
-    expect(list.body.data.items).toHaveLength(1);
+    // 新建订阅时已自动建了该订阅自己的「默认版本」
+    expect(list.body.data.items.map((x: { name: string }) => x.name).sort()).toEqual(["1080p", "默认版本"].sort());
     expect(h.engine.enqueued.some((q) => q.task === "evaluateAcquisition")).toBe(true);
   });