diff --git a/docs/META.md b/docs/META.md
index 7dfc840c..2beb2a4c 100644
--- a/docs/META.md
+++ b/docs/META.md
@@ -332,6 +332,10 @@ Dispatch order per player: `global` → `band` → `bond` (data order) → garri
 → equipped items → EffectRefs (insertion order). `onPrice` runs the priced chess's own 特质 first (购买价格为N sets the
 price that 远见's discount and the strategies' caps then act on). Every call is isolated with try/catch (the error is
 logged once and counted in `match.dispatcher.errors`); nested dispatches are capped at depth 6.
+The equipped-items step walks a snapshot (the owned chess and each holder's items as they stand when it begins) and
+runs an item only if, when its turn comes, it is still equipped on that holder and the holder is still owned: handlers
+move and destroy pieces mid-walk (突变细胞 transforms its holder, normal 博士投影 destroys itself), so an item a handler
+took off is skipped and the item after it still runs; a piece gained or equipped meanwhile waits for the next dispatch.
 
 ### 2.3 Garrisons (特质)
 The dispatcher calls `handler[hook] ?? handler.run` only on the hook of the garrison's `eventType` (a handler may widen
diff --git a/server/match/effectsMeta.js b/server/match/effectsMeta.js
index 720d1702..b9dfadc7 100644
--- a/server/match/effectsMeta.js
+++ b/server/match/effectsMeta.js
@@ -22,7 +22,12 @@
 // 投资人 (investShip) active ⇒ SERVER_GAIN garrisons run ×2 (×3 at ≥ 100 layers) — owned by the dispatcher.
 // ctx.triggerGarrisons(uid, eventType) re-runs another piece's garrisons (铃兰, "触发…的获得时效果", 特质相同).
 // Items: onEquip / onArt / onDestroy go to the item's own handler only; every other hook runs for items equipped on
-// owned chess (ev.source.holder). Dispatch order per player: global → band → bonds → garrisons (board reading order,
+// owned chess (ev.source.holder). That step walks a snapshot — the owned chess and each holder's items as they stand
+// when it begins — and runs an item only if, when its turn comes, it is still equipped on that holder and the holder
+// is still owned: handlers move and destroy pieces mid-walk (突变细胞 transforms its holder and returns the equipment
+// to the hand; normal 博士投影 destroys itself, which splices holder.items), and a live walk skipped the next item or
+// ran it with a holder that was gone. Pieces gained or equipped during the walk wait for the next dispatch.
+// Dispatch order per player: global → band → bonds → garrisons (board reading order,
 // then hand) → equipped items → effects (insertion order); onPrice runs the priced chess's own 特质 first (购买价格为N
 // sets the price the discounts and caps of bonds / strategies then act on — user playtest #5). Every call is
 // try/catch-guarded; nested dispatch depth is capped (MAX_DEPTH) so content can never loop the server.
@@ -207,13 +212,14 @@ export class EffectDispatcher {
       }
       // 4. garrisons (onPrice: already run as step 0)
       if (hook !== 'onPrice') this._garrisons(ps, hook, ev);
-      // 5. equipped items (not for the item-specific hooks)
+      // 5. equipped items (not for the item-specific hooks): a snapshot of the owned chess and of each holder's items,
+      // each run only while still equipped on its still-owned holder — handlers move / destroy pieces (header)
       if (hook !== 'onEquip' && hook !== 'onArt' && hook !== 'onDestroy') {
         for (const holder of ownedChess(ps)) {
-          for (const it of holder.items || []) {
+          for (const it of (holder.items || []).slice()) {
             const key = `item:${itemKey(it.id)}`;
             const h = reg.get(key);
-            if (h) this._call(ps, key, h, hook, { kind: 'item', key, piece: it, holder, item: this.m.gd.item(it.id) }, ev);
+            if (h && stillEquipped(ps, holder, it)) this._call(ps, key, h, hook, { kind: 'item', key, piece: it, holder, item: this.m.gd.item(it.id) }, ev);
           }
         }
       }
@@ -346,6 +352,13 @@ function ownedChess(ps) {
   return out;
 }
 
+/** Dispatch step 5: is `it` still equipped on `holder`, and `holder` still an owned chess of `ps`? */
+function stillEquipped(ps, holder, it) {
+  if (!Array.isArray(holder.items) || !holder.items.includes(it)) return false;
+  const loc = ps.find(holder.uid);
+  return !!loc && loc.piece === holder;
+}
+
 // =====================================================================================================
 // handler context — the ONLY way content mutates player state (see docs/META.md)
 
diff --git a/test/match/feedback1-dispatch-snapshot.test.js b/test/match/feedback1-dispatch-snapshot.test.js
new file mode 100644
index 00000000..84d61824
--- /dev/null
+++ b/test/match/feedback1-dispatch-snapshot.test.js
@@ -0,0 +1,112 @@
+// Prep-effect dispatcher, step 5 (equipped items; server/match/effectsMeta.js): it walks a snapshot of the owned chess
+// and of each holder's items, and an item's hook runs only while that item is still equipped on that holder and the
+// holder is still owned. Handlers move and destroy pieces mid-walk — 突变细胞 (onBattleResult) transforms its holder and
+// sends the equipment back to the hand, normal 博士投影 (onRoundStart) destroys itself and promotes its holder — so the
+// live array either skipped the next item on that holder (a splice shifts it under the loop) or ran it with a holder
+// that was no longer owned. No shipped item has a second onBattleResult / onRoundStart hook, so a synthetic spy handler
+// on an ordinary item (registered in a private registry) stands in for one. DESIGN §21.
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { makeMatch, give, giveItem, DATA } from './harness.js';
+import { createRegistry } from '../../server/match/effectsMeta.js';
+
+const QUIET = { warn() {}, error() {}, info() {} };
+const A = (k) => `chess_item_${k}_e_a`;
+const CELL = A('5_08');
+const PROJECTION = A('5_06'); // 博士投影 (normal): promotes its holder at the next round start, then is gone
+const SPY = A('1_01');        // any item: carries the synthetic spy handler
+const OK = { ok: true };
+
+/** Solo match in PREP R1, everything cleared, with a private registry holding `spy` on SPY. */
+function setup(spy, seed = 3) {
+  const registry = createRegistry({ log: QUIET });
+  registry.item(SPY, spy);
+  const h = makeMatch({ mode: 'solo', humans: 1, seed, registry, fake: true }).start();
+  h.toPrep(1);
+  const m = h.m;
+  for (const ps of m.players.values()) {
+    for (const p of [...ps.board.values(), ...ps.hand.filter(Boolean), ...ps.temp.filter(Boolean)]) if (p.kind === 'chess') ps.returnCopies(p);
+    ps.board.clear(); ps.hand.fill(null); ps.temp.fill(null); ps.offers.length = 0;
+    ps.funds = 50; ps.layers = {}; ps.pendingFunds = 0; ps.shop.freeRefreshes = 0; ps.bandId = null;
+    ps.recompute();
+  }
+  const ps = h.ps('p_0');
+  const equip = (item, target) => m.handle('p_0', { t: 'g.equip', itemUid: item.uid, targetUid: target.uid });
+  return { m, ps, equip };
+}
+/** Visible normal chess whose 特质 are all IN_BATTLE (no prep-side side effects), sorted. */
+const plain = (pred) => Object.values(DATA.chess)
+  .filter((c) => c.visible && !c.isGolden && (c.garrisonIds || []).every((g) => DATA.garrisons[g].eventType === 'IN_BATTLE') && pred(c))
+  .map((c) => c.chessId).sort();
+
+/** What the spy saw: its holder still owned, and itself still equipped on it. */
+function spyCall(ctx) {
+  const { piece, holder } = ctx.source;
+  return { holderOwned: !!ctx.piece(holder.uid), equipped: (holder.items || []).includes(piece) };
+}
+
+test('dispatcher: an item after the 突变细胞 on the same holder is not run with the transformed (gone) holder', () => {
+  for (const order of ['cell first', 'spy first']) {
+    const calls = [];
+    const { m, ps, equip } = setup({ onBattleResult(ctx) { calls.push(spyCall(ctx)); } });
+    const cid = plain((c) => c.tier === 2)[0];
+    const holder = give(m, ps, cid, 'hand');
+    const cell = giveItem(m, ps, CELL);
+    const spy = giveItem(m, ps, SPY);
+    for (const it of order === 'cell first' ? [cell, spy] : [spy, cell]) assert.deepEqual(equip(it, holder), OK);
+    m.dispatch(ps, 'onBattleResult', { result: {}, lpLoss: 0, perfect: true });
+    const chess = ps.hand.filter((p) => p && p.kind === 'chess');
+    assert.equal(chess.length, 1, `${order}: the holder was transformed`);
+    assert.equal(DATA.chess[chess[0].id].tier, 3);
+    assert.ok(ps.hand.some((p) => p && p.uid === spy.uid), `${order}: the spy item is back in the hand`);
+    if (order === 'cell first') {
+      assert.deepEqual(calls, [], 'its holder was gone when its turn came: not run (it was run with a stale holder)');
+    } else {
+      assert.deepEqual(calls, [{ holderOwned: true, equipped: true }], 'run once, before the cell, on its owned holder');
+    }
+  }
+});
+
+test('dispatcher: 博士投影 destroying itself at the round start does not skip the next item on its holder', () => {
+  for (const order of ['projection first', 'spy first']) {
+    const calls = [];
+    const { m, ps, equip } = setup({ onRoundStart(ctx) { calls.push({ ...spyCall(ctx), golden: DATA.chess[ctx.source.holder.id].isGolden }); } });
+    const cid = plain((c) => c.tier === 2)[0];
+    const holder = give(m, ps, cid, 'board', [10, 5]);
+    const proj = giveItem(m, ps, PROJECTION);
+    const spy = giveItem(m, ps, SPY);
+    for (const it of order === 'projection first' ? [proj, spy] : [spy, proj]) assert.deepEqual(equip(it, holder), OK);
+    m.dispatch(ps, 'onRoundStart', { round: 2 });
+    assert.ok(DATA.chess[holder.id].isGolden, `${order}: 博士投影 promoted its holder`);
+    assert.ok(!ps.find(proj.uid), `${order}: 博士投影 is gone`);
+    assert.deepEqual(holder.items.map((it) => it.uid), [spy.uid], `${order}: the spy item stays equipped`);
+    // the projection's splice shifted the spy item under the live loop: it was skipped
+    assert.deepEqual(calls, [{ holderOwned: true, equipped: true, golden: order === 'projection first' }], `${order}: run exactly once`);
+  }
+});
+
+test('dispatcher: an item whose holder an earlier item\'s handler destroyed is not run', () => {
+  const calls = [];
+  const registry = createRegistry({ log: QUIET });
+  const KILLER = A('1_02');
+  let victimUid = null;
+  registry.item(KILLER, { onRoundStart(ctx) { if (victimUid != null) ctx.destroyPiece(victimUid); } });
+  registry.item(SPY, { onRoundStart(ctx) { calls.push(spyCall(ctx)); } });
+  const h = makeMatch({ mode: 'solo', humans: 1, seed: 5, registry, fake: true }).start();
+  h.toPrep(1);
+  const m = h.m;
+  const ps = h.ps('p_0');
+  for (const p of [...ps.board.values(), ...ps.hand.filter(Boolean), ...ps.temp.filter(Boolean)]) if (p.kind === 'chess') ps.returnCopies(p);
+  ps.board.clear(); ps.hand.fill(null); ps.temp.fill(null); ps.offers.length = 0; ps.bandId = null; ps.recompute();
+  const [c1, c2] = plain((c) => c.tier === 1);
+  // board reading order: the killer's holder comes first
+  const first = give(m, ps, c1, 'board', [9, 4]);
+  const victim = give(m, ps, c2, 'hand');
+  victimUid = victim.uid;
+  for (const [it, holder] of [[giveItem(m, ps, KILLER), first], [giveItem(m, ps, SPY), victim]]) {
+    assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: it.uid, targetUid: holder.uid }), OK);
+  }
+  m.dispatch(ps, 'onRoundStart', { round: 2 });
+  assert.ok(!ps.find(victim.uid), 'the victim chess is gone');
+  assert.deepEqual(calls, [], 'the spy on the destroyed holder never ran');
+});