diff --git a/docker-compose.it.yaml b/docker-compose.it.yaml
index 3fb1b16a2..8bb341f0b 100644
--- a/docker-compose.it.yaml
+++ b/docker-compose.it.yaml
@@ -163,3 +163,8 @@ services:
       # RABBITMQ_ENABLED stays "false" (base stack) — it only gates the SMS/email
       # clients, which must remain off. The payment consumer is wired by
       # PAYMENT_RABBITMQ_URL alone.
+      # Drain tail on every pay window. Production defaults to 5 minutes; a
+      # reservation here lives ~60s, so 5 would push every natural expiry past
+      # the suite's 180s timeouts. One minute keeps the tail real and observable
+      # (src/expired-invoice-late-settle.it.ts asserts both sides of it).
+      FREIGHT_PAYMENT_DRAIN_MINUTES: "1"
diff --git a/integration/README.md b/integration/README.md
index b35d682ce..9798fd7f8 100644
--- a/integration/README.md
+++ b/integration/README.md
@@ -57,6 +57,7 @@ gateway-mock-it`) — the code is a read-only mount, not baked into an image.
 | `src/concurrency.it.ts` | duplicate callbacks, two intents on one invoice, wagon budget, pay-window gate |
 | `src/authz.it.ts` | cross-tenant isolation, login audience, service-token gates |
 | `src/cbe-bill.it.ts` | inbound CBE Unified Bill: token → query (hops into freight) → payment |
+| `src/expired-invoice-late-settle.it.ts` | pay-window drain tail; a settlement landing after the hold expired still pays the invoice and revives the booking |
 | `src/bulk-import-full-train.it.ts` | six wheat bookings fill 54 wagons, then gate pass → T1 → dispatch → corridor → arrival → customs tail |
 | `src/bulk-import-waiting-expiry.it.ts` | exact-fill trio selected, waiting three expire with the day |
 | `src/bulk-import-split-promote.it.ts` | partial offer, split on settlement, expiry promotion, exact-remainder rebooking |
@@ -131,6 +132,16 @@ what it actually does and says so in a comment, so a fix fails loudly:
   the phased path (`customs_clearing_enabled` on the contract) avoids it — which
   is why S8's customs tenant is Path B.
 
+- **A live intent makes a hold unexpirable here** (`expired-invoice-late-settle`).
+  Reconcile-before-expire live-queries every non-FAILED intent; the mock answers
+  `PROCESSING` for an unpaid order, which the payment API reads as "money in
+  flight" → `unverifiable` → never expire on unknown. So while a CBE Birr intent
+  is open, NOTHING retires the reservation — not the settle tick, not the staff
+  `bookings/:id/expire` override (it runs the same guard). Producing the
+  expired-invoice-with-a-payment case therefore needs the intent retired first
+  (`status = 'FAILED'`, which reconcile skips), after which a webhook still
+  late-captures it (`applyProviderResult`).
+
 ## Gotchas
 
 - **One unpaid hold per company.** `assertNoUnpaidHold` blocks a company with a
diff --git a/integration/src/expired-invoice-late-settle.it.ts b/integration/src/expired-invoice-late-settle.it.ts
new file mode 100644
index 000000000..6fb57f8c0
--- /dev/null
+++ b/integration/src/expired-invoice-late-settle.it.ts
@@ -0,0 +1,175 @@
+/**
+ * The swallowed late payment
+ * (docs/dev-testing/finding-expired-invoice-swallows-payment.md).
+ *
+ * Settlement is asynchronous — customer taps pay → provider confirms → payment
+ * API enqueues → relay delivers — so the success can land after the booking
+ * window cron has already expired the invoice. Before the fix the money simply
+ * vanished: the intent flipped to SUCCEEDED, `settleByPaymentId` matched no OPEN
+ * invoice and returned null, the relay was told `processed: true`, and the
+ * customer was left debited with an EXPIRED invoice and an EXPIRED booking.
+ *
+ * Two layers are asserted here:
+ *   1. the drain tail — a deadline that just passed does NOT expire anything
+ *      (FREIGHT_PAYMENT_DRAIN_MINUTES, 1 in this stack);
+ *   2. the backstop — a settlement that lands after the drain is treated exactly
+ *      like an in-window payment: invoice PAID, booking PAID.
+ */
+import { afterAll, beforeAll, describe, expect, it } from "vitest";
+import { apiOk, chief, closeDb, db, gateway, poll } from "./client";
+import {
+  createImportSchedule,
+  currentInvoice,
+  departureAt,
+  ensureCorridorRoute,
+  forceWindowOpen,
+  freightPayment,
+  gatewayIntent,
+  invoiceForBooking,
+  payInvoice,
+  prepareBooking,
+  releaseUnpaidHolds,
+  resetCorridorDay,
+  runBatch,
+  type ReadyBooking,
+} from "./flows";
+
+const DEPARTURE = departureAt(4);
+const STAMP = String(Date.now());
+
+/** The stack runs a 1-minute tail (FREIGHT_PAYMENT_DRAIN_MINUTES, docker-compose.it.yaml). */
+const DRAIN_MS = 60_000;
+/** Long enough for several 10s settle ticks, comfortably inside the tail. */
+const INSIDE_TAIL_MS = DRAIN_MS * 0.4;
+
+const bookingRow = async (id: string) =>
+  (
+    await db<{ status: string; payment_status: string; train_schedule_id: string | null }>(
+      `SELECT status, payment_status, train_schedule_id FROM freight.bookings WHERE id = $1`,
+      [id],
+    )
+  )[0];
+
+describe("a payment that lands after the pay window is not swallowed", () => {
+  let booking: ReadyBooking;
+  let invoiceId: string;
+
+  beforeAll(async () => {
+    await gateway.reset();
+    await releaseUnpaidHolds();
+    await ensureCorridorRoute();
+    await resetCorridorDay(DEPARTURE);
+    const schedule = await createImportSchedule({ departure: DEPARTURE });
+    await forceWindowOpen(schedule.id, 45);
+
+    booking = await prepareBooking({
+      suffix: "LATE1",
+      departure: DEPARTURE,
+      runStamp: STAMP,
+      isoSeed: 0,
+      twenty: 2,
+    });
+    await runBatch(schedule.id);
+    invoiceId = (await invoiceForBooking(booking.bookingId)).id;
+  });
+
+  afterAll(closeDb);
+
+  it("holds the reservation while the drain tail runs", async () => {
+    // Deadline just behind now(): the settle tick sees it every 10s and must
+    // leave it alone — this is the customer who tapped pay in the last seconds.
+    await db(
+      `UPDATE freight.bookings SET payment_deadline = now() - interval '5 seconds'
+       WHERE id = $1`,
+      [booking.bookingId],
+    );
+
+    await new Promise((r) => setTimeout(r, INSIDE_TAIL_MS));
+
+    const held = await bookingRow(booking.bookingId);
+    expect(held.status).toBe("SELECTED_FOR_BATCH");
+    // The wagons are still HIS — releasing them at the raw deadline would sell
+    // them to the next customer while his settlement is still in flight.
+    expect(held.train_schedule_id).toBeTruthy();
+    expect((await currentInvoice(invoiceId)).status).not.toBe("EXPIRED");
+  }, 60_000);
+
+  it("expires the hold while the customer's payment is still in flight", async () => {
+    // Open the intent first — payInvoice refuses once dueAt is behind us, which
+    // is the point: no NEW payment may start, only an in-flight one may land.
+    const res = await payInvoice(invoiceId, { method: "CBE_BIRR" });
+    expect(res.status, JSON.stringify(res.body)).toBeLessThanOrEqual(201);
+
+    const intent = await gatewayIntent(booking.bookingId);
+    expect(intent.status).toBe("REQUIRES_ACTION");
+    expect((await currentInvoice(invoiceId)).payment_id).toBeTruthy();
+
+    // The provider reported a failure and we retired the intent — the same shape
+    // the payment API's own sweep writes. This is what makes the hold expirable:
+    // reconcile-before-expire skips FAILED candidates (intents.service.ts:412)
+    // and answers a clean "not paid". While the intent is live the mock answers
+    // PROCESSING → `unverifiable` → NOTHING expires the hold, not the settle tick
+    // and not staff. The money can still land afterwards: `applyProviderResult`
+    // registers a late capture on a retired intent (intents.service.ts:576).
+    await db(
+      `UPDATE edr_payment.payment_intent SET status = 'FAILED' WHERE id = $1`,
+      [intent.id],
+    );
+    await apiOk(chief, "post", `/api/train-scheduling/bookings/${booking.bookingId}/expire`);
+
+    const expired = await poll<{ status: string }>(
+      "invoice EXPIRED with the hold",
+      `SELECT status FROM freight.invoices WHERE id = $1`,
+      [invoiceId],
+      (row) => row?.status === "EXPIRED",
+      { attempts: 20, intervalMs: 2000 },
+    );
+    expect(expired.status).toBe("EXPIRED");
+    expect((await bookingRow(booking.bookingId)).status).toBe("EXPIRED");
+    // The settlement correlation key survives the expiry — `paymentId` is what
+    // settleByPaymentId looks the invoice up by when the money finally lands.
+    const linked = (await currentInvoice(invoiceId)).payment_id!;
+    expect((await freightPayment(linked)).merchant_order_id).toBe(
+      intent.merchant_order_id,
+    );
+  }, 180_000);
+
+  it("settles the EXPIRED invoice and revives the booking when the money lands", async () => {
+    const intent = await gatewayIntent(booking.bookingId);
+    const res = await gateway.webhook({ merchantOrderId: intent.merchant_order_id });
+    expect(res.body.delivered).toBe(200);
+
+    const settled = await poll<{ status: string }>(
+      "payment intent SUCCEEDED",
+      `SELECT status FROM edr_payment.payment_intent WHERE id = $1`,
+      [intent.id],
+      (row) => row?.status === "SUCCEEDED",
+      { attempts: 20, intervalMs: 1000 },
+    );
+    expect(settled.status).toBe("SUCCEEDED");
+
+    // The bug: this row used to sit at EXPIRED with paid_amount null forever,
+    // because settleByPaymentId only matched OPEN_STATUSES.
+    const invoice = await poll<{ status: string; paid_amount: string; balance_amount: string }>(
+      "expired invoice settled by the late payment",
+      `SELECT status, paid_amount, balance_amount FROM freight.invoices WHERE id = $1`,
+      [invoiceId],
+      (row) => row?.status === "PAID",
+      { attempts: 30, intervalMs: 2000 },
+    );
+    expect(Number(invoice.paid_amount)).toBeGreaterThan(0);
+    expect(Number(invoice.balance_amount)).toBe(0);
+
+    // …and the second swallow point: advanceBookingOnPayment used to refuse an
+    // EXPIRED booking outright, so the money landed on a booking that stayed dead.
+    const revived = await poll<{ status: string }>(
+      "expired booking revived by the late payment",
+      `SELECT status FROM freight.bookings WHERE id = $1`,
+      [booking.bookingId],
+      (row) => row?.status === "PAID",
+      { attempts: 30, intervalMs: 2000 },
+    );
+    expect(revived.status).toBe("PAID");
+    expect((await bookingRow(booking.bookingId)).payment_status).toBe("PAID");
+  }, 180_000);
+});