diff --git a/packages/engine/src/__tests__/executor-pause.test.ts b/packages/engine/src/__tests__/executor-pause.test.ts
index e2acc80b48..e3667b32d9 100644
--- a/packages/engine/src/__tests__/executor-pause.test.ts
+++ b/packages/engine/src/__tests__/executor-pause.test.ts
@@ -14,6 +14,7 @@ import { generateWorktreeName, slugify } from "../worktree-names.js";
 import type { Task, TaskDetail } from "@fusion/core";
 import { SessionManager } from "@earendil-works/pi-coding-agent";
 import { StepSessionExecutor } from "../step-session-executor.js";
+import { activeSessionRegistry } from "../active-session-registry.js";
 import { executorLog } from "../logger.js";
 import { withRateLimitRetry } from "../rate-limit-retry.js";
 import { runVerificationCommand as mockedRunVerificationCommand } from "../verification-utils.js";
@@ -1041,11 +1042,13 @@ describe("TaskExecutor agent execution flow (FN-978)", () => {
         steer: vi.fn(),
       };
 
-      // Simulate an active session
-      (executor as any).activeSessions.set("FN-001", {
+      const worktreePath = "/tmp/test/.worktrees/fn-001";
+      (executor as any).addActiveWorktree("FN-001", worktreePath);
+      (executor as any).setActiveSession("FN-001", {
         session: mockSession,
         seenSteeringIds: new Set(),
-      });
+      }, worktreePath);
+      expect(activeSessionRegistry.isPathActive(worktreePath)).toBe(true);
 
       const task = {
         id: "FN-001",
@@ -1070,6 +1073,7 @@ describe("TaskExecutor agent execution flow (FN-978)", () => {
       // Verify session was disposed and removed from map
       expect(disposeSpy).toHaveBeenCalled();
       expect((executor as any).activeSessions.has("FN-001")).toBe(false);
+      expect(activeSessionRegistry.isPathActive(worktreePath)).toBe(false);
       // Verify task was added to pausedAborted set
       expect((executor as any).pausedAborted.has("FN-001")).toBe(true);
     });
@@ -1085,8 +1089,10 @@ describe("TaskExecutor agent execution flow (FN-978)", () => {
         cleanup: vi.fn().mockResolvedValue(undefined),
       };
 
-      // Simulate an active step executor
-      (executor as any).activeStepExecutors.set("FN-002", mockStepExecutor as any);
+      const worktreePath = "/tmp/test/.worktrees/fn-002";
+      (executor as any).addActiveWorktree("FN-002", worktreePath);
+      (executor as any).setActiveStepExecutor("FN-002", mockStepExecutor as any, worktreePath);
+      expect(activeSessionRegistry.isPathActive(worktreePath)).toBe(true);
 
       const task = {
         id: "FN-002",
@@ -1112,6 +1118,42 @@ describe("TaskExecutor agent execution flow (FN-978)", () => {
       expect(mockTerminateAllSessions).toHaveBeenCalled();
       // Verify removed from map
       expect((executor as any).activeStepExecutors.has("FN-002")).toBe(false);
+      expect(activeSessionRegistry.isPathActive(worktreePath)).toBe(false);
+    });
+
+    it("terminates active workflow-step session when task is moved away", async () => {
+      const store = createMockStore();
+      const executor = new TaskExecutor(store, "/tmp/test");
+      const worktreePath = "/tmp/test/.worktrees/fn-006";
+      const abort = vi.fn().mockResolvedValue(undefined);
+      const dispose = vi.fn();
+
+      (executor as any).addActiveWorktree("FN-006", worktreePath);
+      (executor as any).setActiveWorkflowStepSession("FN-006", { abort, dispose } as any, worktreePath);
+      expect(activeSessionRegistry.isPathActive(worktreePath)).toBe(true);
+
+      const task = {
+        id: "FN-006",
+        title: "Test Task",
+        description: "Test",
+        column: "todo" as const,
+        dependencies: [],
+        steps: [],
+        currentStep: 0,
+        log: [],
+        createdAt: new Date().toISOString(),
+        updatedAt: new Date().toISOString(),
+      };
+
+      store._trigger("task:moved", { task, from: "in-progress", to: "triage" });
+
+      await waitForAsyncExpectation(() => {
+        expect(abort).toHaveBeenCalled();
+      });
+
+      expect(dispose).toHaveBeenCalled();
+      expect((executor as any).activeWorkflowStepSessions.has("FN-006")).toBe(false);
+      expect(activeSessionRegistry.isPathActive(worktreePath)).toBe(false);
     });
 
     it("handles graceful no-op when no active session exists", async () => {
diff --git a/packages/engine/src/__tests__/executor-test-helpers.ts b/packages/engine/src/__tests__/executor-test-helpers.ts
index 641277b269..8a17d1e403 100644
--- a/packages/engine/src/__tests__/executor-test-helpers.ts
+++ b/packages/engine/src/__tests__/executor-test-helpers.ts
@@ -289,7 +289,7 @@ import { hydrateWorktreeDb } from "../worktree-db-hydrate.js";
 import { classifyTaskWorktree, describeRegisteredWorktrees, isUsableTaskWorktree } from "../worktree-pool.js";
 import { classifyStaleLock, tryRemoveStaleLock } from "../worktree-stale-lock.js";
 import { parseStaleRegistrationPath, recoverStaleRegistration } from "../worktree-stale-registration.js";
-import { executingTaskLock } from "../active-session-registry.js";
+import { activeSessionRegistry, executingTaskLock } from "../active-session-registry.js";
 
 export const mockedCreateFnAgent = vi.mocked(createFnAgent);
 export const mockedSessionManager = vi.mocked(SessionManager);
@@ -438,9 +438,7 @@ export function resetExecutorMocks() {
   mockTerminateAllSessions.mockResolvedValue(undefined);
   mockCleanup.mockResolvedValue(undefined);
   mockSteerActiveSessions.mockResolvedValue(undefined);
-  // FN-4811 follow-up: the executingTaskLock is process-wide module state, so it must
-  // be cleared between tests or earlier tests' claims will block later tests' execute()
-  // calls ("expected at least 2 createFnAgent calls but got 0" / "expected not called
-  // but called 3 times" symptoms in executor-pause / executor-prompt tests).
+  // FNXC:ExecutorTests 2026-06-24-21:09: Executor liveness guards are process-wide module state, so test reset must clear both executing locks and active-session registry paths; otherwise earlier tests' claims can block later execute() calls with duplicate-execution or foreign active-session path symptoms.
   executingTaskLock._clearForTest();
+  activeSessionRegistry.clear();
 }
diff --git a/packages/engine/src/__tests__/executor-worktree.test.ts b/packages/engine/src/__tests__/executor-worktree.test.ts
index d521447ac7..c7e24d7a7e 100644
--- a/packages/engine/src/__tests__/executor-worktree.test.ts
+++ b/packages/engine/src/__tests__/executor-worktree.test.ts
@@ -2174,7 +2174,7 @@ describe("TaskExecutor worktree pool integration", () => {
       return "" as any;
     });
     mockedExec.mockImplementation(((cmd: any, _opts: any, cb: any) => {
-      if (String(cmd).includes("git merge-base HEAD origin/main")) {
+      if (String(cmd).includes("git merge-base HEAD")) {
         cb(null, "newbase123\n", "");
         return {} as any;
       }
diff --git a/packages/engine/src/__tests__/reliability-interactions/owning-node-unavailable-interactions.test.ts b/packages/engine/src/__tests__/reliability-interactions/owning-node-unavailable-interactions.test.ts
index da1d315671..19be468dfe 100644
--- a/packages/engine/src/__tests__/reliability-interactions/owning-node-unavailable-interactions.test.ts
+++ b/packages/engine/src/__tests__/reliability-interactions/owning-node-unavailable-interactions.test.ts
@@ -263,7 +263,7 @@ describe("reliability interactions: owning-node unavailable handoff", () => {
     await scheduler.schedule();
 
     expect(store.logEntry).toHaveBeenCalledWith(task.id, expect.stringContaining("Owning-node handoff applied"));
-    expect(store.updateTask).toHaveBeenCalledWith(task.id, expect.objectContaining({ effectiveNodeId: null }));
     expect(store.moveTask).toHaveBeenCalledWith(task.id, "in-progress", expect.any(Object));
+    expect(store.updateTask).not.toHaveBeenCalledWith(task.id, expect.objectContaining({ effectiveNodeId: "node-b" }));
   });
 });
diff --git a/packages/engine/src/__tests__/restart.integration.test.ts b/packages/engine/src/__tests__/restart.integration.test.ts
index d366de61fe..60bf4b4444 100644
--- a/packages/engine/src/__tests__/restart.integration.test.ts
+++ b/packages/engine/src/__tests__/restart.integration.test.ts
@@ -1096,7 +1096,13 @@ describe("Scheduler after restart", () => {
 
     expect(store.moveTask).toHaveBeenCalledWith("FN-070", "in-progress", expect.objectContaining({ allocateWorktree: expect.any(Function) }));
     expect(store.updateTask).toHaveBeenCalledWith("FN-070", expect.objectContaining({ status: null, blockedBy: null }));
-    expect(onSchedule).toHaveBeenCalledWith(todoTask);
+    expect(onSchedule).toHaveBeenCalledWith(expect.objectContaining({
+      id: todoTask.id,
+      column: "in-progress",
+      effectiveNodeSource: "local",
+      dispatchStormCount: 1,
+      blockedBy: undefined,
+    }));
   });
 
   it("schedule() respects dependency ordering — blocked tasks stay in todo", async () => {