diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 4717da652fc..4a7c9d1e39e 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -571,6 +571,15 @@ jobs:
           src/main/runtime/worktree-scan-admin-fingerprint-gate.test.ts
           src/shared/secure-file-fsync-flags.test.ts
 
+      - name: Build Electron app for Windows terminal lifecycle E2E
+        run: pnpm exec electron-vite build --mode e2e
+
+      - name: Run Windows terminal close lifecycle regression
+        env:
+          SKIP_BUILD: '1'
+          ORCA_E2E_FORWARD_APP_LOGS: '1'
+        run: pnpm run test:e2e tests/e2e/windows-headless-terminal-close-lifecycle.spec.ts --workers=1
+
       # Why the :parallel variant: identical to build:release except the three
       # electron-vite targets overlap instead of running back to back. The Linux package
       # job already packages and smoke-tests an AppImage built that way.
diff --git a/src/main/runtime/orca-runtime.test.ts b/src/main/runtime/orca-runtime.test.ts
index 5095cea186c..3589d886636 100644
--- a/src/main/runtime/orca-runtime.test.ts
+++ b/src/main/runtime/orca-runtime.test.ts
@@ -31475,9 +31475,10 @@ describe('OrcaRuntimeService', () => {
       })
     )
     const kill = vi.fn(() => true)
+    const closeTerminal = vi.fn()
     const closeTerminalTab = vi.fn(async () => {})
     const runtime = new OrcaRuntimeService(runtimeStore as never)
-    runtime.setNotifier({ closeTerminalTab } as never)
+    runtime.setNotifier({ closeTerminal, closeTerminalTab } as never)
     runtime.setPtyController({
       write: () => true,
       kill,
@@ -31526,6 +31527,7 @@ describe('OrcaRuntimeService', () => {
       ptyKilled: true
     })
     expect(kill).toHaveBeenCalledWith(ptyId)
+    expect(closeTerminal).toHaveBeenCalledWith('host-tab')
     expect(closeTerminalTab).not.toHaveBeenCalled()
     expect(getSession().tabsByWorktree[TEST_WORKTREE_ID]).toEqual([])
     expect((await runtime.listMobileSessionTabs(`id:${TEST_WORKTREE_ID}`)).tabs).toEqual([])
@@ -31576,6 +31578,113 @@ describe('OrcaRuntimeService', () => {
     expect((await runtime.listMobileSessionTabs(`id:${TEST_WORKTREE_ID}`)).tabs).not.toEqual([])
   })
 
+  it('does not settle a missing mobile projection while the renderer still owns the parent', () => {
+    const { runtimeStore } = makeRuntimeStoreWithWorkspaceSession(getDefaultWorkspaceSession())
+    const runtime = new OrcaRuntimeService(runtimeStore as never)
+    runtime.syncWindowGraph(1, {
+      tabs: [
+        {
+          tabId: 'host-tab',
+          worktreeId: TEST_WORKTREE_ID,
+          title: 'Headless worker',
+          activeLeafId: HEADLESS_LEAF_ID,
+          layout: null
+        }
+      ],
+      leaves: []
+    })
+    const isAlreadyRetired = (
+      runtime as unknown as {
+        isAlreadyRetiredMobileTerminalSurfaceError: (
+          error: Error,
+          worktreeId: string,
+          parentTabId: string
+        ) => boolean
+      }
+    ).isAlreadyRetiredMobileTerminalSurfaceError.bind(runtime)
+
+    expect(isAlreadyRetired(new Error('tab_not_found'), TEST_WORKTREE_ID, 'host-tab')).toBe(false)
+  })
+
+  it('keeps a split sibling when exit retires the addressed leaf before an unconfirmed stop returns', async () => {
+    const tabId = '33333333-3333-4333-8333-333333333333'
+    const leftPtyId = 'headless-split-left'
+    const rightPtyId = 'headless-split-right'
+    const layout = makeHeadlessTerminalLayout({
+      [HEADLESS_LEAF_ID]: leftPtyId,
+      [HEADLESS_SECOND_LEAF_ID]: rightPtyId
+    })
+    const { runtimeStore, getSession } = makeRuntimeStoreWithWorkspaceSession(
+      makeWorkspaceSessionWithHeadlessTerminal({
+        activeTabId: tabId,
+        activeTabIdByWorktree: { [TEST_WORKTREE_ID]: tabId },
+        tabsByWorktree: {
+          [TEST_WORKTREE_ID]: [
+            {
+              id: tabId,
+              ptyId: leftPtyId,
+              worktreeId: TEST_WORKTREE_ID,
+              title: 'Split workers',
+              customTitle: null,
+              color: null,
+              sortOrder: 0,
+              createdAt: 1
+            }
+          ]
+        },
+        terminalLayoutsByTabId: { [tabId]: layout }
+      })
+    )
+    let runtime!: OrcaRuntimeService
+    let tabIdsAfterExit: string[] = []
+    const kill = vi.fn(() => false)
+    const stopAndWait = vi.fn(async (ptyId: string) => {
+      runtime.onPtyExit(ptyId, 0)
+      tabIdsAfterExit = (await runtime.listMobileSessionTabs(`id:${TEST_WORKTREE_ID}`)).tabs.map(
+        (tab) => tab.id
+      )
+      return false
+    })
+    runtime = new OrcaRuntimeService({ ...runtimeStore, flushOrThrow: vi.fn() } as never)
+    runtime.setPtyController({
+      write: () => true,
+      kill,
+      stopAndWait,
+      getForegroundProcess: async () => null,
+      listProcesses: async () => []
+    })
+    runtime.registerPty(leftPtyId, TEST_WORKTREE_ID, null, {
+      tabId,
+      leafId: HEADLESS_LEAF_ID
+    })
+    runtime.registerPty(rightPtyId, TEST_WORKTREE_ID, null, {
+      tabId,
+      leafId: HEADLESS_SECOND_LEAF_ID
+    })
+    runtime.syncWindowGraph(0, { tabs: [], leaves: [] })
+    await runtime.listMobileSessionTabs(`id:${TEST_WORKTREE_ID}`)
+    const rightHandle = runtime.preAllocateHandleForPty(rightPtyId)
+
+    await expect(runtime.closeTerminal(rightHandle)).resolves.toMatchObject({
+      handle: rightHandle,
+      tabId,
+      ptyKilled: false,
+      ptyStopVerdict: 'unverifiable'
+    })
+
+    expect(stopAndWait).toHaveBeenCalledWith(rightPtyId, expect.anything())
+    expect(tabIdsAfterExit).toEqual([`${tabId}::${HEADLESS_LEAF_ID}`])
+    expect(kill).toHaveBeenCalledWith(rightPtyId)
+    expect(kill).not.toHaveBeenCalledWith(leftPtyId)
+    expect(getSession().tabsByWorktree[TEST_WORKTREE_ID]).toHaveLength(1)
+    expect(getSession().terminalLayoutsByTabId[tabId]?.ptyIdsByLeafId).toMatchObject({
+      [HEADLESS_LEAF_ID]: leftPtyId
+    })
+    expect(
+      (await runtime.listMobileSessionTabs(`id:${TEST_WORKTREE_ID}`)).tabs.map((tab) => tab.id)
+    ).toEqual([`${tabId}::${HEADLESS_LEAF_ID}`])
+  })
+
   it('keeps the renderer close transaction for an adopted runtime-owned tab', async () => {
     // The renderer pin state can be newer than the debounced session, so once adopted its live close guard must win over stale persisted metadata.
     const servePtyId = 'serve-adopted-1'
diff --git a/src/main/runtime/orca-runtime.ts b/src/main/runtime/orca-runtime.ts
index 8de190f392d..d7d6deede5b 100644
--- a/src/main/runtime/orca-runtime.ts
+++ b/src/main/runtime/orca-runtime.ts
@@ -29161,7 +29161,7 @@ export class OrcaRuntimeService {
   private findMobileTerminalSurface(
     worktreeId: string,
     parentTabId: string,
-    options: { requireReady?: boolean } = {}
+    options: { leafId?: string; requireReady?: boolean } = {}
   ): RuntimeMobileSessionCreateTerminalResult | null {
     const snapshot = this.mobileSessionTabsByWorktree.get(worktreeId)
     if (!snapshot) {
@@ -29169,7 +29169,10 @@ export class OrcaRuntimeService {
     }
     const result = this.toMobileSessionTabsResult(snapshot)
     const tab = result.tabs.find(
-      (candidate) => candidate.type === 'terminal' && candidate.parentTabId === parentTabId
+      (candidate) =>
+        candidate.type === 'terminal' &&
+        candidate.parentTabId === parentTabId &&
+        (options.leafId === undefined || candidate.leafId === options.leafId)
     )
     if (!tab || tab.type !== 'terminal') {
       return null
@@ -29192,7 +29195,9 @@ export class OrcaRuntimeService {
   ): boolean {
     // Why: missing persistence is ambiguous while a sibling or stale live publication still owns the surface.
     return (
-      error.message === 'tab_not_found' && !this.findMobileTerminalSurface(worktreeId, parentTabId)
+      error.message === 'tab_not_found' &&
+      !this.tabs.has(parentTabId) &&
+      !this.findMobileTerminalSurface(worktreeId, parentTabId)
     )
   }
 
@@ -29208,7 +29213,7 @@ export class OrcaRuntimeService {
           candidate.parentLayout?.ptyIdsByLeafId?.[candidate.leafId] === ptyId)
     )
     return tab?.type === 'terminal'
-      ? this.findMobileTerminalSurface(worktreeId, tab.parentTabId)
+      ? this.findMobileTerminalSurface(worktreeId, tab.parentTabId, { leafId: tab.leafId })
       : null
   }
 
@@ -29795,9 +29800,8 @@ export class OrcaRuntimeService {
     if (pty) {
       // Why: PTY exit can immediately replace a ready SSH publication with a pending one, so capture its durable HUB surface before killing it.
       const surface =
-        (pty.pty.tabId
-          ? this.findMobileTerminalSurface(pty.pty.worktreeId, pty.pty.tabId)
-          : null) ?? this.findMobileTerminalSurfaceForPty(pty.pty.worktreeId, pty.pty.ptyId)
+        this.findMobileTerminalSurfaceForPty(pty.pty.worktreeId, pty.pty.ptyId) ??
+        (pty.pty.tabId ? this.findMobileTerminalSurface(pty.pty.worktreeId, pty.pty.tabId) : null)
       const tabId = surface?.tab.parentTabId ?? pty.pty.tabId ?? pty.record.tabId
       // Why: relay recovery can leave stale renderer leaves; the persisted HUB layout defines whether closing this PTY closes the whole surface.
       const siblingCount = surface?.tab.parentLayout
@@ -29831,7 +29835,16 @@ export class OrcaRuntimeService {
         return this.describeTerminalClose(handle, tabId, pty.pty.ptyId, ptyKilled)
       }
       const ptyKilled = await this.stopExplicitlyClosedTabPtys([pty.pty.ptyId], pty.pty.ptyId)
-      if (!ptyKilled || siblingCount <= 1) {
+      // Why: an exit callback can retire the addressed split leaf before an unconfirmed stop returns; parent fallback would destroy its surviving siblings.
+      const addressedSplitSurfaceRetired =
+        siblingCount > 1 &&
+        surface !== null &&
+        !this.mobileSessionSnapshotHasSurface(
+          pty.pty.worktreeId,
+          surface.tab.parentTabId,
+          surface.tab.leafId
+        )
+      if ((!ptyKilled || siblingCount <= 1) && !addressedSplitSurfaceRetired) {
         if (surface) {
           // Why: paired viewers keep ended streams mounted until the HUB publishes removal, so explicit close uses the durable host-tab transaction instead of viewer-local exit handling.
           try {