diff --git a/backend/app/api/ledger.py b/backend/app/api/ledger.py
index cdad6346..2fe472ec 100644
--- a/backend/app/api/ledger.py
+++ b/backend/app/api/ledger.py
@@ -249,7 +249,10 @@ async def certify_dismiss(payload: DismissIn, session: AsyncSession = Depends(ge
     """「不是口径」：记一条审计（ledger.certify.dismiss），这一项之后不再进队。"""
     from app.ledger import certify
 
+    from app.api.deps import current_principal
+
     if payload.kind is not None and payload.kind not in certify.KINDS:
         raise HTTPException(422, "可沉淀的问题只有三种：确定性重复、问题聚类、被反复用的答案")
-    await certify.dismiss(session, payload.item_id, kind=payload.kind, note=payload.note)
+    await certify.dismiss(session, payload.item_id, kind=payload.kind, note=payload.note,
+                          principal=current_principal())
     return {"ok": True, "item_id": payload.item_id}
diff --git a/backend/app/chat/questions.py b/backend/app/chat/questions.py
index 0c99e042..99d61240 100644
--- a/backend/app/chat/questions.py
+++ b/backend/app/chat/questions.py
@@ -18,6 +18,12 @@
 聚类用 memory/embeddings 的向量贪心聚：按时间从新到旧，和某一类的种子足够像就并进去，否则自立一类。本地向量是词频
 哈希、语义能力弱，结果是下限——调用方据 embedder 照实写明用的是哪个向量模型。
 
+**类的 id 由成员定。** 每个问题有稳定的 id（Question.key：问数据是那一轮，别的探索运行是那次运行），一类的 id
+（QuestionCluster.id）是成员的 id 排好之后取的哈希：同一批问题两次读取，类的 id 一样。以前按种子问题的原文算，种子是一类里
+最新的那一句，同一批问题时间相同的几句先后不定、来了一句新的问法种子就换了，「不是口径」按 id 记就失效了。同一时刻问的
+几句按 id 排出先后（recent_questions），不靠库里读出来的先后。来了新成员 id 照样会变：认证队列按成员记「不是口径」
+（ledger/certify），不只按 id。
+
 **向量只取一次。** 同一批问题会被聚很多遍：评测页「口径命中与重复度」一次打开，/api/evals/signals 按窗口调 compute_stats
 （缺省 6 个窗口，每个都聚一次），页面另调 /api/ledger/stats；认证队列、治理页的探索问题聚类也各聚一遍。配了远程向量模型时
 每聚一遍都把几百句问题重新发一次，页面慢、还花钱。所以问题原文 → 向量在进程里留一份（_vectors：最多 VECTOR_CACHE_MAX 句，
@@ -28,6 +34,7 @@
 from __future__ import annotations
 
 import asyncio
+import hashlib
 import weakref
 from collections import OrderedDict
 from collections.abc import Sequence
@@ -55,6 +62,16 @@ class Question:
     workflow: str | None = None
     origin: str | None = None
 
+    @property
+    def key(self) -> str:
+        """稳定的 id：问数据的那一轮（turn:…），别的探索运行是那次运行（run:…）；两样都没有的按原文和时间。"""
+        if self.turn_id:
+            return f"turn:{self.turn_id}"
+        if self.run_id:
+            return f"run:{self.run_id}"
+        stamp = self.at.isoformat() if self.at is not None else ""
+        return "text:" + hashlib.sha256(f"{self.text}\n{stamp}".encode()).hexdigest()[:16]
+
 
 @dataclass
 class QuestionCluster:
@@ -66,6 +83,16 @@ class QuestionCluster:
     def count(self) -> int:
         return len(self.members)
 
+    @property
+    def keys(self) -> list[str]:
+        """成员的稳定 id，排好的。"""
+        return sorted(q.key for q in self.members)
+
+    @property
+    def id(self) -> str:
+        """类的 id：成员的稳定 id 排好之后取哈希（见模块说明）。同一批问题两次读取一样。"""
+        return hashlib.sha256("\n".join(self.keys).encode()).hexdigest()[:16]
+
 
 async def recent_questions(session: AsyncSession, principal: Any, *, limit: int) -> list[Question]:
     """最近问过的问题，从新到旧，最多 limit 条（取法见模块开头）。principal 用来去掉这个人读不了的只给拥有者的运行。"""
@@ -94,7 +121,8 @@ async def recent_questions(session: AsyncSession, principal: Any, *, limit: int)
         text = (payload or {}).get("question") if isinstance(payload, dict) else None
         if isinstance(text, str) and text.strip():
             out.append(Question(text=text.strip(), at=at, run_id=run_id, workflow=workflow, origin=origin))
-    out.sort(key=lambda q: q.at.timestamp() if q.at is not None else 0.0, reverse=True)
+    # 同一时刻问的几句按稳定的 id 排：库里读出来的先后不定，种子、聚类的结果就跟着变（见模块说明）
+    out.sort(key=lambda q: (q.at.timestamp() if q.at is not None else 0.0, q.key), reverse=True)
     return out[:limit]
 
 
diff --git a/backend/app/ledger/certify.py b/backend/app/ledger/certify.py
index 3892a763..049c9ba7 100644
--- a/backend/app/ledger/certify.py
+++ b/backend/app/ledger/certify.py
@@ -11,7 +11,9 @@
   位置（按规范形里的先后对齐）是参数候选，不变的是口径常量。展示的是代表那条的规范文本（字面量都换成了「?」，不带取值）。
   这一项的 id 按（数据源、规范形）算；以前按规范文本记的「不是口径」照样认（组里任何一条的规范文本对得上就算）；
 - 问题聚类（cluster）：app/chat/questions 全站唯一的聚类（只取问题原文、不含 history、排除系统派生的运行），≥ REPEAT_RUNS
-  个问题的类；
+  个问题的类。这一项的 id 是类的 id（成员的稳定 id 排好取哈希：同一批问题两次读取一样）；「不是口径」记下当时的成员，之后
+  这一类过半的成员是那时记下的就照样不进队（来了几句新问法 id 会变，按成员认就不失效）。以前按种子问题原文算的 id 记的
+  照样认，记的成员读不懂的照实忽略；
 - 被反复用的答案（reused）：导出过 ≥ 2 次（report.exported 审计，第 2 波）、做成过应用（蓝图的来源是这次运行）、在画布里
   打开过或提取过（工作流的 origin.run_id 是这次运行）的轮次。
 每项给代表问题、轮次链接、（shape 的）SQL 形状和参数候选、有没有相关口径（可以对账的那份）、是不是已经固化过（frozen_into，
@@ -241,6 +243,27 @@ async def _dismissed(session: Any) -> set[str]:
         AuditEvent.action == DISMISS_ACTION, AuditEvent.subject_kind == SUBJECT_KIND))).all() if sid}
 
 
+async def _dismissed_members(session: Any) -> list[set[str]]:
+    """问题聚类上点过「不是口径」时记下的成员（每条一组稳定 id）。老记录没记成员、记的读不懂（不是字符串列表）的不算。"""
+    from app.db.models import AuditEvent
+
+    out: list[set[str]] = []
+    for (data,) in (await session.execute(select(AuditEvent.data).where(
+            AuditEvent.action == DISMISS_ACTION, AuditEvent.subject_kind == SUBJECT_KIND))).all():
+        members = data.get("members") if isinstance(data, dict) else None
+        if isinstance(members, list) and members and all(isinstance(m, str) and m for m in members):
+            out.append(set(members))
+    return out
+
+
+def _cluster_dismissed(cluster: Any, dismissed: set[str], members: list[set[str]]) -> bool:
+    """这一类点过「不是口径」没有：类的 id 记过；以前按种子问题原文算的 id 记过；或者过半的成员是某一次记下的。"""
+    if f"cluster:{cluster.id}" in dismissed or item_id("cluster", " ".join(cluster.members[0].text.split())) in dismissed:
+        return True
+    keys = set(cluster.keys)
+    return any(len(keys & seen) * 2 > len(keys) for seen in members)
+
+
 async def _frozen(session: Any) -> dict[str, list[dict[str, Any]]]:
     """来源运行 → 从它固化出的工作流 [{workflow_id, name, status, published_version}]（origin.sources）。"""
     from app.db.models import Workflow
@@ -279,6 +302,7 @@ async def queue(session: Any, *, principal: Any) -> dict[str, Any]:
     from app.ledger import store
 
     dismissed = await _dismissed(session)
+    dismissed_members = await _dismissed_members(session)
     frozen = await _frozen(session)
     kinds = {name: kind for name, kind in (await session.execute(select(DataSource.name, DataSource.kind))).all()}
     runs = list((await session.execute(select(Run).where(
@@ -360,8 +384,8 @@ async def queue(session: Any, *, principal: Any) -> dict[str, Any]:
         if cluster.count < REPEAT_RUNS:
             continue
         seed = cluster.members[0]
-        iid = item_id("cluster", " ".join(seed.text.split()))
-        if iid in dismissed:
+        iid = f"cluster:{cluster.id}"
+        if _cluster_dismissed(cluster, dismissed, dismissed_members):
             continue
         items.append({"id": iid, "kind": "cluster", "question": seed.text, "count": cluster.count,
                       "turns": [{"run_id": q.run_id, "turn_id": q.turn_id, "question": q.text}
@@ -415,12 +439,25 @@ async def _reused(session: Any, runs: list[Run], turns: dict[str, dict[str, Any]
     return out
 
 
-async def dismiss(session: Any, iid: str, *, kind: str | None = None, note: str | None = None) -> None:
-    """「不是口径」：写一条审计，之后这一项不再进队。"""
+async def dismiss(session: Any, iid: str, *, kind: str | None = None, note: str | None = None,
+                  principal: Any = None) -> None:
+    """「不是口径」：写一条审计，之后这一项不再进队。问题聚类另记下这一类现在的成员（服务端按同一批问题重新聚一次找到
+    这一类，不收客户端传的成员；找不到——这会儿问题又多了、聚出来的已经不是这一类——就只记 id，照实）。"""
     from app.auth.audit import record
 
+    members: list[str] = []
+    if principal is not None and (kind == "cluster" or iid.startswith("cluster:")):
+        from app.chat.questions import cluster_questions, recent_questions
+
+        try:
+            questions = await recent_questions(session, principal, limit=QUESTION_LIMIT)
+            found = next((c for c in await cluster_questions(questions) if f"cluster:{c.id}" == iid), None) \
+                if questions else None
+            members = found.keys if found is not None else []
+        except Exception:  # noqa: BLE001 - 取向量出错：只记 id，「不是口径」照样记上
+            logger.exception("「不是口径」时重新聚类出错，只按 id 记")
     await record(session, DISMISS_ACTION, SUBJECT_KIND, iid,
-                 data={k: v for k, v in {"kind": kind, "note": note}.items() if v})
+                 data={k: v for k, v in {"kind": kind, "note": note, "members": members}.items() if v})
     await session.commit()
 
 
diff --git a/backend/tests/test_ledger_certify.py b/backend/tests/test_ledger_certify.py
index 1431921c..5ecbbbd5 100644
--- a/backend/tests/test_ledger_certify.py
+++ b/backend/tests/test_ledger_certify.py
@@ -347,3 +347,78 @@ async def test_a_not_a_caliber_recorded_by_the_old_text_id_still_counts(client,
     res = await client.post("/api/ledger/certify-queue/dismiss", json={"item_id": old, "kind": "shape"})
     assert res.status_code == 200
     assert shape_items((await client.get("/api/ledger/certify-queue")).json()) == []
+
+
+# --------------------------------------------------------------------------
+# 问题聚类的 id 由成员定；「不是口径」按成员记
+# --------------------------------------------------------------------------
+
+
+async def test_cluster_ids_come_from_the_members_and_do_not_change_between_reads():
+    from datetime import datetime, timezone
+
+    from app.chat.questions import Question, QuestionCluster, cluster_questions
+
+    at = datetime(2026, 10, 1, tzinfo=timezone.utc)
+    # 同一时刻问的三句（时间相同，库里读出来的先后不定）：两次读出来先后不同，种子就不同，类的 id 仍然一样
+    texts = ["仓库乙本月出库多少件", "仓库乙本月出库多少件？", "仓库乙本月出库了多少件"]
+    questions = [Question(text=t, at=at, turn_id=f"t-{i}") for i, t in enumerate(texts)]
+    first = await cluster_questions(questions)
+    again = await cluster_questions(list(reversed(questions)))
+    assert len(first) == 1 and len(again) == 1 and first[0].members[0].text != again[0].members[0].text
+    assert [c.id for c in first] == [c.id for c in again]
+    assert first[0].keys == ["turn:t-0", "turn:t-1", "turn:t-2"]
+    assert QuestionCluster(members=list(reversed(questions))).id == first[0].id
+    # 成员不同，id 就不同
+    assert QuestionCluster(members=questions[:2]).id != first[0].id
+
+
+async def test_not_a_caliber_on_a_cluster_survives_a_new_member_and_old_records_still_count(client, monkeypatch):
+    import uuid
+
+    from app.auth.audit import record
+
+    text = f"仓库甲本周入库了多少件（{uuid.uuid4().hex[:6]}）"
+    a, b = await conversation(), await conversation()
+    asked = {(await ask(monkeypatch, conv, weekly(*WEEKS[0]), question=text)).id for conv in (a, a, b)}
+
+    async def mine() -> list[dict]:
+        body = (await client.get("/api/ledger/certify-queue")).json()
+        return [i for i in body["items"] if i["kind"] == "cluster" and asked & {t["run_id"] for t in i["turns"]}]
+
+    [item] = await mine()
+    [again] = await mine()
+    assert item["id"] == again["id"], "同一批问题两次读取，类的 id 一样"
+    # 读不懂的老记录照实忽略：不报错、不把这一类藏起来
+    async with SessionLocal() as session:
+        await record(session, certify.DISMISS_ACTION, certify.SUBJECT_KIND, "cluster:0000000000000000",
+                     data={"kind": "cluster", "members": "看不懂"})
+        await session.commit()
+    assert [i["id"] for i in await mine()] == [item["id"]]
+
+    res = await client.post("/api/ledger/certify-queue/dismiss", json={"item_id": item["id"], "kind": "cluster"})
+    assert res.status_code == 200
+    assert await mine() == []
+    # 再换个说法问一句：成员多了一个、种子换成了新的这句，类的 id 变了；过半的成员是点「不是口径」时记下的，照样不进队
+    newer = await ask(monkeypatch, b, weekly(*WEEKS[1]), question=text + "？")
+    asked.add(newer.id)
+    assert await mine() == []
+
+
+async def test_a_not_a_caliber_recorded_by_the_old_seed_text_id_still_counts(client, monkeypatch):
+    import uuid
+
+    from app.auth.audit import record
+
+    text = f"仓库丙上周退货多少件（{uuid.uuid4().hex[:6]}）"
+    a, b = await conversation(), await conversation()
+    for conv in (a, a, b):
+        await ask(monkeypatch, conv, weekly(*WEEKS[0]), question=text)
+    body = (await client.get("/api/ledger/certify-queue")).json()
+    assert [i for i in body["items"] if i["kind"] == "cluster" and i["question"] == text]
+    async with SessionLocal() as session:
+        await record(session, certify.DISMISS_ACTION, certify.SUBJECT_KIND, certify.item_id("cluster", text),
+                     data={"kind": "cluster"})
+        await session.commit()
+    body = (await client.get("/api/ledger/certify-queue")).json()
+    assert not [i for i in body["items"] if i["kind"] == "cluster" and i["question"] == text]