diff --git a/server/src/services/automatic-sandbox-continuation.test.ts b/server/src/services/automatic-sandbox-continuation.test.ts
index 18bcf750c3..26b3911b9e 100644
--- a/server/src/services/automatic-sandbox-continuation.test.ts
+++ b/server/src/services/automatic-sandbox-continuation.test.ts
@@ -145,6 +145,15 @@ const support = await getEmbeddedPostgresTestSupport();
     await heartbeatService(db).resumeInterruptedSandboxRuns();
     expect(await successors(f.run.id)).toHaveLength(1);
   });
+  it("does not revive old work if a later run completes between preparation and scheduling", async () => {
+    const f = await seed();
+    expect(await prepareAutomaticSandboxContinuation(db, f.run)).not.toBeNull();
+    await db.insert(heartbeatRuns).values({ companyId: f.companyId, agentId: f.agentId, status: "succeeded",
+      startedAt: new Date(), finishedAt: new Date(), contextSnapshot: { issueId: f.issueId } });
+    const result = await heartbeatService(db).scheduleBoundedRetry(f.run.id);
+    expect(result.outcome).toBe("not_scheduled");
+    expect(await successors(f.run.id)).toHaveLength(0);
+  });
   it("finishes delivery after a crash between retiring the hold and scheduling", async () => {
     const f = await seed();
     expect(await prepareAutomaticSandboxContinuation(db, f.run)).not.toBeNull();
diff --git a/server/src/services/automatic-sandbox-continuation.ts b/server/src/services/automatic-sandbox-continuation.ts
index ba7dd30486..d1c0e3eb99 100644
--- a/server/src/services/automatic-sandbox-continuation.ts
+++ b/server/src/services/automatic-sandbox-continuation.ts
@@ -15,6 +15,17 @@ export async function runHasUnconfirmedRemoteExecution(db: Db, companyId: string
   return leases.some(lease => lease.provider && lease.provider !== "local" && !hasRemoteTerminationReceipt(lease));
 }
 
+export async function hasLaterSandboxExecution(db: Db, run: typeof heartbeatRuns.$inferSelect, issueId: string) {
+  const [successor] = await db.select({ id: heartbeatRuns.id }).from(heartbeatRuns).where(and(
+      eq(heartbeatRuns.companyId, run.companyId),
+      sql`(${heartbeatRuns.retryOfRunId} = ${run.id} or
+        (coalesce(${heartbeatRuns.nativeIssueId}::text, ${heartbeatRuns.contextSnapshot}->>'issueId') = ${issueId}::text
+          and ${heartbeatRuns.createdAt} > ${run.createdAt.toISOString()}
+          and (${heartbeatRuns.startedAt} is not null or ${heartbeatRuns.status} in ('queued', 'running', 'scheduled_retry', 'succeeded'))))`,
+    )).limit(1);
+  return Boolean(successor);
+}
+
 /** Repair execution ownership independently of whether task admission is open.
  * A fresh conversation can inspect unknown prior effects; a stopped sandbox is
  * the prerequisite, not a user accepting responsibility for those effects. */
@@ -39,14 +50,7 @@ export async function prepareAutomaticSandboxContinuation(db: Db, source: typeof
     const recorded = await recordedRunAdapter(tx as unknown as Db, run);
     if (recorded && !isConversationAdapter(recorded)) return null;
     // A later execution owns current task work. Never revive an older request.
-    const [successor] = await tx.select({ id: heartbeatRuns.id }).from(heartbeatRuns).where(and(
-      eq(heartbeatRuns.companyId, run.companyId),
-      sql`(${heartbeatRuns.retryOfRunId} = ${run.id} or
-        (coalesce(${heartbeatRuns.nativeIssueId}::text, ${heartbeatRuns.contextSnapshot}->>'issueId') = ${issue.id}::text
-          and ${heartbeatRuns.createdAt} > ${run.createdAt.toISOString()}
-          and (${heartbeatRuns.startedAt} is not null or ${heartbeatRuns.status} in ('queued', 'running', 'scheduled_retry', 'succeeded'))))`,
-    )).limit(1);
-    if (successor) return null;
+    if (await hasLaterSandboxExecution(tx as unknown as Db, run, issue.id)) return null;
     const leases = await tx.select().from(environmentLeases).where(and(
       eq(environmentLeases.companyId, run.companyId), eq(environmentLeases.heartbeatRunId, run.id),
     ));
diff --git a/server/src/services/heartbeat.ts b/server/src/services/heartbeat.ts
index 5150f9b79b..1d81a460ea 100644
--- a/server/src/services/heartbeat.ts
+++ b/server/src/services/heartbeat.ts
@@ -1,5 +1,5 @@
 import { PROCESS_IDENTITY_RECORDED, recordNativeLocalProcessStop } from "./native-local-process-stop.js";
-import { prepareAutomaticSandboxContinuation, runHasUnconfirmedRemoteExecution, SANDBOX_INFRASTRUCTURE_ERRORS } from "./automatic-sandbox-continuation.js";
+import { hasLaterSandboxExecution, prepareAutomaticSandboxContinuation, runHasUnconfirmedRemoteExecution, SANDBOX_INFRASTRUCTURE_ERRORS } from "./automatic-sandbox-continuation.js";
 import { LegacyControllerLeaseLostError, legacyControllerBootId, legacyControllerClaim, hasLiveLegacyController, revokeExpiredLegacyController, watchLegacyControllerLease } from "./legacy-controller-lease.js";
 import { completeTerminatedRemoteNativeSessionCleanup } from "../vendor/paperclip-runner/index.js";
 import { remoteExecutionHasStopped, remoteTerminationReceipt, stoppedRemoteCleanupScopes } from "./remote-execution-termination.js";
@@ -15063,6 +15063,13 @@ export function heartbeatService(
               reusedExisting: true,
             };
         }
+        // Preparation and scheduling can be separated by a crash or another
+        // admission. Recheck latest execution while holding the issue lock.
+        if (issueId && parseObject(run.resultJson?.automaticSandboxRecovery).state === "provider_terminated" &&
+            await hasLaterSandboxExecution(tx as unknown as Db, run, issueId)) {
+          return { outcome: "not_scheduled", reason: "A later execution owns the current task",
+            errorCode: "issue_execution_lock_changed", issueId, details: { runId: run.id } };
+        }
         if (retryReason === INTERACTION_CONTINUATION_INFRA_RETRY_REASON) {
           if (issueId) {
             await tx.execute(