diff --git a/src/pages/outbound/outbound.vue b/src/pages/outbound/outbound.vue
index 3875c66..ee1cf5c 100644
--- a/src/pages/outbound/outbound.vue
+++ b/src/pages/outbound/outbound.vue
@@ -7,14 +7,14 @@
 				<view v-if="current" class="detail-toolbar"><view><text class="detail-kicker">当前任务</text><text class="detail-title">出库作业详情</text></view><button :disabled="busy" @tap="closeTask">‹ 返回列表</button></view>
 				<view class="fulfillment-card">
 					<ScanTargetInput name="outbound" :model-value="scanCode" :label="discardCurrent ? '废弃订单托盘码' : '任务号、出库单号、排车单号、托盘码或箱码'" :placeholder="discardCurrent ? '扫描废弃订单对应托盘码' : '扫描任务号 / 出库单号 / 排车单号 / 托盘码 / 箱码'" :active="true" @update:modelValue="updateScanCode" @submit="handleScan" />
-					<button class="secondary-button" :disabled="!scanCode || loading || busy" @tap="handleScan(scanCode)">{{ discardCurrent ? '打开废弃托盘' : current ? '匹配出库货物' : '打开出库任务' }}</button>
+					<button class="secondary-button" :disabled="!scanCode || loading || busy || discardLoading || discardBusy" @tap="handleScan(scanCode)">{{ discardCurrent ? '打开废弃托盘' : current ? '匹配出库货物' : '打开出库任务' }}</button>
 					<text class="scan-help">任务号直接恢复；退货整托出库扫托盘码，散箱出库扫箱唛。</text>
 				</view>
 
 				<view v-if="loading" class="fulfillment-state"><text>正在加载出库任务…</text></view>
-				<view v-else-if="error" class="fulfillment-error" role="alert"><text class="state-title">{{ error.message }}</text><text v-if="error.code">错误码：{{ error.code }}</text><text v-if="error.requestId">requestId：{{ error.requestId }}</text><text v-if="error.traceId">traceId：{{ error.traceId }}</text><text v-if="error.network" class="offline-note">网络连接失败，当前任务、扫码草稿和幂等键均已保留。</text><button class="secondary-button" :disabled="loading || busy" @tap="retry">重试</button></view>
+				<view v-else-if="error" class="fulfillment-error" role="alert"><text class="state-title">{{ error.message }}</text><text v-if="error.code">错误码：{{ error.code }}</text><text v-if="error.requestId">requestId：{{ error.requestId }}</text><text v-if="error.traceId">traceId：{{ error.traceId }}</text><text v-if="error.network" class="offline-note">网络连接失败，当前任务、扫码草稿和幂等键均已保留。</text><button class="secondary-button" :disabled="loading || busy || discardLoading || discardBusy" @tap="retry">重试</button></view>
 
-				<template v-if="!loading && !current">
+				<template v-if="!loading && !current && !discardCurrent">
 					<view class="list-toolbar"><view><text class="list-title">待处理出库任务</text><text class="list-count">{{ tasks.length }} 个任务</text></view><button :disabled="loading" @tap="loadTasks">刷新</button></view>
 					<view v-if="tasks.length" class="task-list">
 						<button v-for="task in tasks" :key="task.taskNo" class="task-card" @tap="openTask(task.taskNo)"><view class="task-head"><view class="task-code-row"><text class="business-code">{{ task.taskNo || '—' }}</text><text v-if="task.taskNo === recentTaskNo" class="recent-badge">上次作业</text></view><text class="status-badge">{{ statusLabel(task.status) }}</text></view><text class="task-meta">出库单 {{ task.outboundNo || '—' }} · {{ taskType(task) }}</text><text class="task-enter">查看并开始出库 ›</text></button>
@@ -74,11 +74,12 @@
 			pickedPackages() { return (this.current?.items || []).reduce((total, item) => total + item.pickedPackages, 0) },
 			remainingPackages() { return Math.max(0, this.plannedPackages - this.pickedPackages) },
 			selectedRemaining() { return Math.max(0, Math.min(Number(this.selectedItem?.plannedPackages || 0) - Number(this.selectedItem?.pickedPackages || 0), Number(this.selectedPosition?.availablePackages || 0))) },
-			canPick() { return this.current?.status !== 'COMPLETED' && this.selectedItem && this.selectedPosition && Number(this.packages) > 0 && Number(this.packages) <= this.selectedRemaining },
-			canComplete() { return this.plannedPackages > 0 && this.remainingPackages === 0 && this.current?.status !== 'COMPLETED' },
+			taskOperable() { return ['PENDING', 'IN_PROGRESS'].includes(this.current?.status) },
+			canPick() { return this.taskOperable && this.selectedItem && this.selectedPosition && Number(this.packages) > 0 && Number(this.packages) <= this.selectedRemaining },
+			canComplete() { return this.plannedPackages > 0 && this.remainingPackages === 0 && this.taskOperable },
 			discardOrders() { const groups = new Map(); for (const task of this.discardTasks) { const current = groups.get(task.discardNo) || { discardNo: task.discardNo, palletCount: 0, pendingPalletCount: 0 }; current.palletCount += 1; if (task.status !== 'COMPLETED') current.pendingPalletCount += 1; groups.set(task.discardNo, current) } return [...groups.values()] },
 			discardOrderCount() { return this.discardOrders.length },
-			canConfirmDiscard() { return Boolean(this.discardTask && this.discardTask.status !== 'COMPLETED' && this.discardTask.skus.length && this.discardTask.skus.every((sku) => Number.isInteger(Number(this.discardActuals[sku.itemId])) && Number(this.discardActuals[sku.itemId]) >= 0 && Number(this.discardActuals[sku.itemId]) <= sku.plannedPackages)) }
+			canConfirmDiscard() { return Boolean(!this.discardLoading && !this.discardBusy && this.discardTask && this.discardTask.status !== 'COMPLETED' && this.discardTask.skus.length && this.discardTask.skus.every((sku) => Number.isInteger(Number(this.discardActuals[sku.itemId])) && Number(this.discardActuals[sku.itemId]) >= 0 && Number(this.discardActuals[sku.itemId]) <= sku.plannedPackages)) }
 		},
 		onShow() { if (!requireSession()) return; this.user = session.currentUser; restoreFulfillmentDraft(`${this.user?.id || ''}:${this.user?.warehouseId || ''}`); this.startScanner(); if (!this.bootstrapped) { this.bootstrapped = true; this.scanCode = ''; this.loadTasks(); return } if (this.current?.taskNo) this.openTask(this.current.taskNo); else this.loadTasks() },
 		onHide() { this.stopScanner() },
@@ -106,31 +107,45 @@
 				}, true)
 			},
 			closeTask() { this.current = null; this.selectedItem = null; this.selectedPosition = null; this.error = null; this.successMessage = ''; updateFulfillmentDraft('outbound', { currentTaskNo: '', scanCode: '', packages: 1 }); this.loadTasks() },
-			openDiscardOrder(discardNo) { const code = String(discardNo || '').trim(); if (!code) return; this.discardCurrent = { discardNo: code }; this.discardTask = null; this.discardPalletCode = ''; this.discardActuals = {}; this.error = null },
-			closeDiscard() { this.discardCurrent = null; this.discardTask = null; this.discardPalletCode = ''; this.discardActuals = {}; this.loadTasks() },
+			openDiscardOrder(discardNo) { const code = String(discardNo || '').trim(); if (!code || this.discardBusy || this.busy || this.loading) return; this.current = null; this.discardLoading = false; this.discardCurrent = { discardNo: code }; this.discardTask = null; this.discardPalletCode = ''; this.discardActuals = {}; this.error = null },
+			closeDiscard() { if (this.discardBusy) return; this.discardLoading = false; this.discardCurrent = null; this.discardTask = null; this.discardPalletCode = ''; this.discardActuals = {}; this.loadTasks() },
 			updateDiscardPalletCode(value) { this.discardPalletCode = value },
-			async resolveDiscardPallet(raw) { const code = String(raw?.detail?.value ?? raw ?? this.discardPalletCode).trim(); if (!code || !this.discardCurrent || this.discardBusy) return; this.discardPalletCode = code; this.discardLoading = true; try { const task = await resolveCargoDiscardPallet(code); if (task.discardNo !== this.discardCurrent.discardNo) throw new Error('扫描的托盘不属于当前废弃订单'); this.discardTask = normalizeCargoDiscardTask(task); this.discardActuals = Object.fromEntries(this.discardTask.skus.map((sku) => [sku.itemId, sku.actualPackages == null ? sku.plannedPackages : sku.actualPackages])) } catch (error) { this.setError(error, '废弃托盘读取失败') } finally { this.discardLoading = false } },
+			async resolveDiscardPallet(raw) {
+				const code = String(raw?.detail?.value ?? raw ?? this.discardPalletCode).trim()
+				if (!code || !this.discardCurrent || this.discardBusy || this.discardLoading) return
+				const order = this.discardCurrent
+				this.discardPalletCode = code; this.discardLoading = true; this.discardTask = null; this.discardActuals = {}; this.error = null
+				try {
+					const task = await resolveCargoDiscardPallet(code)
+					if (this.discardCurrent !== order) return
+					if (task.discardNo !== order.discardNo) throw new Error('扫描的托盘不属于当前废弃订单')
+					this.discardTask = normalizeCargoDiscardTask(task)
+					this.discardActuals = Object.fromEntries(this.discardTask.skus.map((sku) => [sku.itemId, sku.actualPackages == null ? sku.plannedPackages : sku.actualPackages]))
+				} catch (error) { if (this.discardCurrent === order) this.setError(error, '废弃托盘读取失败') }
+				finally { if (this.discardCurrent === order) this.discardLoading = false }
+			},
 			updateDiscardActual(itemId, event) { const value = Math.max(0, Math.trunc(Number(event.detail.value || 0))); this.discardActuals = { ...this.discardActuals, [itemId]: value } },
-			async confirmDiscard() { if (!this.canConfirmDiscard || !this.discardTask || !this.discardCurrent) return; this.discardBusy = true; try { const lines = this.discardTask.skus.map((sku) => ({ itemId: sku.itemId, actualPackages: Number(this.discardActuals[sku.itemId]) })); await confirmCargoDiscard(this.discardCurrent.discardNo, this.discardTask.palletNo, lines); this.successMessage = '废弃出库作业已完成，等待仓库确认'; this.discardPalletCode = ''; this.discardTask = null; this.discardTasks = await listCargoDiscardTasks(); playSuccessSound() } catch (error) { this.setError(error, '废弃出库失败') } finally { this.discardBusy = false } },
+			async confirmDiscard() { if (this.discardBusy || this.discardLoading || !this.canConfirmDiscard || !this.discardTask || !this.discardCurrent) return; this.discardBusy = true; try { const lines = this.discardTask.skus.map((sku) => ({ itemId: sku.itemId, actualPackages: Number(this.discardActuals[sku.itemId]) })); await confirmCargoDiscard(this.discardCurrent.discardNo, this.discardTask.palletNo, lines); this.successMessage = '废弃出库作业已完成，等待仓库确认'; this.discardPalletCode = ''; this.discardTask = null; this.discardTasks = await listCargoDiscardTasks(); playSuccessSound() } catch (error) { this.setError(error, '废弃出库失败') } finally { this.discardBusy = false } },
 			handleScan(raw) {
-				const code = String(raw?.detail?.value ?? raw ?? this.scanCode).trim(); if (!code || this.busy || this.loading) return
+				const code = String(raw?.detail?.value ?? raw ?? this.scanCode).trim(); if (!code || this.busy || this.loading || this.discardBusy || this.discardLoading) return
 				console.info('[Overseas PDA outbound] scan', { code, task: this.current?.taskNo || '', discard: this.discardCurrent?.discardNo || '' }); this.scanCode = code; updateFulfillmentDraft('outbound', { scanCode: code })
 				if (this.discardCurrent) return this.resolveDiscardPallet(code)
 				if (!this.current) return this.openScannedTask(code)
 				if (code === this.current.taskNo || code === this.current.outboundNo) return this.openTask(this.current.taskNo)
+				if (!this.taskOperable) return
 				if ((this.current.items || []).some((item) => item.palletNo === code)) return this.submitPalletPick(code)
 				if (this.findAndSelectPosition(code)) return
 				this.setError(new Error('扫码未匹配当前出库任务的托盘码、箱码、SKU 或入仓码'), '扫码未匹配')
 			},
 			findAndSelectPosition(code, feedback = true) { for (const item of this.current?.items || []) { if (this.current?.outboundType === 'RETURN_OUTBOUND' && item.palletNo) continue; const position = item.positions.find((value) => value.availablePackages > 0 && [value.palletNo, value.cartonMark, value.skuCode, value.inboundCode].filter(Boolean).includes(code)); if (position) { this.selectPosition(item, position, code); if (feedback) playSuccessSound(); return true } } return false },
-			selectPosition(item, position, scannedCode = '') { if (!position || position.availablePackages <= 0 || (this.current?.outboundType === 'RETURN_OUTBOUND' && item.palletNo)) return; this.selectedItem = item; this.selectedPosition = position; this.selectedScanCode = scannedCode || this.lineBusinessCode(position); updateFulfillmentDraft('outbound', { scanCode: this.selectedScanCode, packages: Math.max(1, Math.min(item.plannedPackages - item.pickedPackages, position.availablePackages)) }) },
+			selectPosition(item, position, scannedCode = '') { if (!this.taskOperable || !position || position.availablePackages <= 0 || (this.current?.outboundType === 'RETURN_OUTBOUND' && item.palletNo)) return; this.selectedItem = item; this.selectedPosition = position; this.selectedScanCode = scannedCode || this.lineBusinessCode(position); updateFulfillmentDraft('outbound', { scanCode: this.selectedScanCode, packages: Math.max(1, Math.min(item.plannedPackages - item.pickedPackages, position.availablePackages)) }) },
 			async submitPick() {
 				if (!this.canPick) return
 				const payload = outboundPickPayload(this.selectedItem, this.selectedPosition, this.packages, this.selectedScanCode); const key = fulfillmentIdempotencyKey('outbound', 'pick', { taskNo: this.current.taskNo, ...payload })
 				await this.run('提交出库拣货', async () => { await pickOutboundTask(this.current.taskNo, { ...payload, idempotencyKey: key.value }); this.current = await getOutboundTask(this.current.taskNo); releaseFulfillmentKey('outbound', key.signature); this.selectedItem = null; this.selectedPosition = null; this.selectedScanCode = ''; updateFulfillmentDraft('outbound', { scanCode: '', packages: 1 }); this.successMessage = '本次出库拣货已记录'; playSuccessSound() })
 			},
 			async submitPalletPick(palletNo) {
-				const code = String(palletNo || '').trim(); if (!code || !this.current) return
+				const code = String(palletNo || '').trim(); if (!code || !this.taskOperable) return
 				const key = fulfillmentIdempotencyKey('outbound', 'pallet-pick', { taskNo: this.current.taskNo, palletNo: code })
 				await this.run('整托拣货', async () => { await pickOutboundPallet(this.current.taskNo, code, { idempotencyKey: key.value }); this.current = await getOutboundTask(this.current.taskNo); releaseFulfillmentKey('outbound', key.signature); this.selectedItem = null; this.selectedPosition = null; updateFulfillmentDraft('outbound', { scanCode: '', packages: 1 }); this.successMessage = `${code} 整托拣货已完成`; playSuccessSound() })
 			},
@@ -139,7 +154,7 @@
 				const key = fulfillmentIdempotencyKey('outbound', 'complete', { taskNo: this.current.taskNo })
 				await this.run('完成出库任务', async () => { await completeOutboundTask(this.current.taskNo, { idempotencyKey: key.value }); this.current = await getOutboundTask(this.current.taskNo); releaseFulfillmentKey('outbound', key.signature); this.successMessage = '出库任务已完成'; playSuccessSound() })
 			},
-			async retry() { if (this.current?.taskNo) await this.openTask(this.current.taskNo); else if (fulfillment.outbound.currentTaskNo) await this.openTask(fulfillment.outbound.currentTaskNo); else if (this.scanCode) await this.openScannedTask(this.scanCode); else await this.loadTasks() },
+			async retry() { if (this.discardCurrent) { if (this.discardPalletCode) await this.resolveDiscardPallet(this.discardPalletCode); return } if (this.current?.taskNo) await this.openTask(this.current.taskNo); else if (fulfillment.outbound.currentTaskNo) await this.openTask(fulfillment.outbound.currentTaskNo); else if (this.scanCode) await this.openScannedTask(this.scanCode); else await this.loadTasks() },
 			async run(action, work, loading = false) { if (this.busy || this.loading) return; this.error = null; this.successMessage = ''; if (loading) this.loading = true; else { this.busy = true; this.busyAction = action.includes('完成') ? 'complete' : 'pick' } try { await work() } catch (error) { this.setError(error, `${action}失败`) } finally { this.loading = false; this.busy = false; this.busyAction = '' } },
 			setError(error, fallback) { const forbidden = ['403', 'A0403'].includes(String(error?.code || '')); this.error = { message: forbidden ? '当前账号没有海外仓 PDA 作业权限，请联系管理员授权' : error?.message || fallback, code: error?.code, requestId: error?.requestId, traceId: error?.traceId, network: Boolean(error?.network) }; console.error('[Overseas PDA outbound] failed', this.error); playErrorSound() },
 			lineBusinessCode(position) { return position?.cartonMark || position?.palletNo || position?.skuCode || position?.inboundCode || '业务码缺失' },
diff --git a/tests/outbound-lifecycle.test.mjs b/tests/outbound-lifecycle.test.mjs
new file mode 100644
index 0000000..a77f491
--- /dev/null
+++ b/tests/outbound-lifecycle.test.mjs
@@ -0,0 +1,83 @@
+import test from 'node:test'
+import assert from 'node:assert/strict'
+import { readFileSync } from 'node:fs'
+
+const source = readFileSync(new URL('../src/pages/outbound/outbound.vue', import.meta.url), 'utf8').match(/<script>([\s\S]*?)<\/script>/)[1]
+const deferred = () => { let resolve; const promise = new Promise(done => { resolve = done }); return { promise, resolve } }
+function page(overrides = {}) {
+  const calls = []
+  const deps = { PortalHeader: {}, ScanTargetInput: {}, session: { currentUser: {} }, fulfillment: { outbound: { packages: 1, currentTaskNo: 'OLD-TASK' } },
+    updateFulfillmentDraft() {}, fulfillmentIdempotencyKey: () => ({ value: 'key', signature: 'signature' }), releaseFulfillmentKey() {},
+    playErrorSound() {}, playSuccessSound() {}, pickOutboundPallet: async () => calls.push('pick'), completeOutboundTask: async () => calls.push('complete'),
+    getOutboundTask: async () => ({ taskNo: 'TASK', status: 'COMPLETED', items: [] }), normalizeCargoDiscardTask: value => value,
+    ...overrides }
+  const definition = new Function(...Object.keys(deps), source.replace(/^\s*import .*$/gm, '').replace('export default', 'return'))(...Object.values(deps))
+  const vm = definition.data()
+  for (const [name, fn] of Object.entries(definition.methods)) vm[name] = fn.bind(vm)
+  for (const [name, fn] of Object.entries(definition.computed)) Object.defineProperty(vm, name, { get: () => fn.call(vm) })
+  return { vm, calls }
+}
+
+test('completed and cancelled tasks cannot submit pallet picking or task completion', async () => {
+  for (const status of ['COMPLETED', 'CANCELLED']) {
+    const { vm, calls } = page()
+    vm.current = { taskNo: 'TASK', status, items: [{ palletNo: 'PALLET', plannedPackages: 1, pickedPackages: 1, positions: [] }] }
+    await vm.handleScan('PALLET'); await vm.submitPalletPick('PALLET'); await vm.completeTask()
+    assert.deepEqual(calls, [])
+  }
+})
+
+test('pending and in-progress tasks still submit exactly once while busy', async () => {
+  for (const status of ['PENDING', 'IN_PROGRESS']) {
+    const pending = deferred(); let submits = 0
+    const { vm } = page({ pickOutboundPallet: async () => { submits++; await pending.promise } })
+    vm.current = { taskNo: 'TASK', status, items: [{ palletNo: 'PALLET', plannedPackages: 1, pickedPackages: 0, positions: [] }] }
+    const first = vm.handleScan('PALLET'); const second = vm.handleScan('PALLET')
+    pending.resolve(); await Promise.all([first, second]); assert.equal(submits, 1)
+  }
+})
+
+test('failed new pallet lookup clears the previous selectable pallet and preserves retry code', async () => {
+  const { vm } = page({ resolveCargoDiscardPallet: async () => { throw new Error('offline') } })
+  vm.discardCurrent = { discardNo: 'DISCARD' }; vm.discardTask = { palletNo: 'OLD', status: 'PENDING', skus: [] }
+  await vm.resolveDiscardPallet('NEW')
+  assert.equal(vm.discardTask, null); assert.equal(vm.canConfirmDiscard, false)
+  assert.equal(vm.discardPalletCode, 'NEW'); assert.equal(vm.error.message, 'offline'); assert.equal(vm.discardLoading, false)
+})
+
+test('discard pallet scans do not overlap and cannot leave the previous pallet ready to submit', async () => {
+  const pending = deferred(); let resolves = 0
+  const { vm } = page({ resolveCargoDiscardPallet: async () => { resolves++; return pending.promise } })
+  vm.discardCurrent = { discardNo: 'DISCARD' }; vm.discardTask = { palletNo: 'OLD', status: 'PENDING', skus: [{ itemId: 'sku', plannedPackages: 1 }] }; vm.discardActuals = { sku: 1 }
+  const first = vm.resolveDiscardPallet('NEW')
+  const second = vm.resolveDiscardPallet('SECOND')
+  const canConfirmDuringLoad = vm.canConfirmDiscard
+  pending.resolve({ discardNo: 'DISCARD', palletNo: 'NEW', status: 'PENDING', skus: [] }); await Promise.all([first, second])
+  assert.equal(resolves, 1); assert.equal(canConfirmDuringLoad, false)
+  assert.equal(vm.discardTask.palletNo, 'NEW')
+})
+
+test('discard confirmation is guarded against double submission', async () => {
+  const pending = deferred(); let submits = 0
+  const { vm } = page({ confirmCargoDiscard: async () => { submits++; await pending.promise }, listCargoDiscardTasks: async () => [] })
+  vm.discardCurrent = { discardNo: 'DISCARD' }; vm.discardTask = { palletNo: 'PALLET', status: 'PENDING', skus: [{ itemId: 'sku', plannedPackages: 1 }] }; vm.discardActuals = { sku: 1 }
+  const first = vm.confirmDiscard(); const second = vm.confirmDiscard()
+  pending.resolve(); await Promise.all([first, second]); assert.equal(submits, 1)
+})
+
+test('discard retry stays in the discard workflow instead of restoring an old outbound task', async () => {
+  const { vm } = page(); const calls = []
+  vm.discardCurrent = { discardNo: 'DISCARD' }; vm.discardPalletCode = 'PALLET'
+  vm.resolveDiscardPallet = async code => calls.push(['discard', code]); vm.openTask = async code => calls.push(['outbound', code])
+  await vm.retry(); assert.deepEqual(calls, [['discard', 'PALLET']])
+})
+
+test('closing or switching discard order ignores the previous resolve response', async () => {
+  const pending = deferred()
+  const { vm } = page({ resolveCargoDiscardPallet: () => pending.promise })
+  vm.discardCurrent = { discardNo: 'FIRST' }
+  const first = vm.resolveDiscardPallet('PALLET')
+  vm.openDiscardOrder('SECOND')
+  pending.resolve({ discardNo: 'FIRST', palletNo: 'PALLET', skus: [] }); await first
+  assert.equal(vm.discardTask, null); assert.equal(vm.error, null)
+})