diff --git a/CHANGELOG.md b/CHANGELOG.md
index a28745bb73c..7f61d985116 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ Docs: https://docs.openclaw.ai
 - Infra/net: fix multipart FormData fields (including `model`) being silently dropped when a guarded runtime fetch body crosses a FormData implementation boundary, restoring OpenAI audio transcription requests that failed with HTTP 400. (#64349) Thanks @petr-sloup.
 - Plugins/memory: restore cached memory capability public artifacts on plugin-registry cache hits so memory-backed artifact surfaces stay visible after warm loads. Thanks @sercada and @vincentkoc.
 - Gateway/cron: preserve requested isolated-agent config across runtime reloads so subagent jobs and heartbeat overrides keep the right workspace and heartbeat settings when the hot-loaded snapshot is stale. Thanks @l0cka and @vincentkoc.
+- Cron/isolated sessions: persist the right transcript path for each isolated run, including fresh session rollovers, so cron runs stop appending to stale session files. Thanks @samrusani and @vincentkoc.
 
 ## 2026.4.11
 
diff --git a/src/cron/isolated-agent.session-identity.test.ts b/src/cron/isolated-agent.session-identity.test.ts
index f2f345378a7..36df45280f4 100644
--- a/src/cron/isolated-agent.session-identity.test.ts
+++ b/src/cron/isolated-agent.session-identity.test.ts
@@ -15,6 +15,9 @@ import {
   runCronTurn,
   withTempHome,
 } from "./isolated-agent.turn-test-helpers.js";
+import { setupRunCronIsolatedAgentTurnSuite } from "./isolated-agent/run.suite-helpers.js";
+
+setupRunCronIsolatedAgentTurnSuite();
 
 describe("runCronIsolatedAgentTurn session identity", () => {
   beforeEach(() => {
@@ -101,6 +104,22 @@ describe("runCronIsolatedAgentTurn session identity", () => {
     });
   });
 
+  it("passes sessionFile to isolated cron runs", async () => {
+    await withTempHome(async (home) => {
+      await runCronTurn(home, {
+        jobPayload: DEFAULT_AGENT_TURN_PAYLOAD,
+      });
+      const call = vi.mocked(runEmbeddedPiAgent).mock.calls.at(-1)?.[0] as {
+        sessionFile?: string;
+      };
+
+      expect(call?.sessionFile).toContain(
+        path.join(home, ".openclaw", "agents", "main", "sessions"),
+      );
+      expect(call?.sessionFile?.endsWith(".jsonl")).toBe(true);
+    });
+  });
+
   it("starts a fresh session id for each cron run", async () => {
     await withTempHome(async (home) => {
       const storePath = await writeSessionStore(home, { lastProvider: "webchat", lastTo: "" });
diff --git a/src/cron/isolated-agent.turn-test-helpers.ts b/src/cron/isolated-agent.turn-test-helpers.ts
index 18de2530ac7..8bdb413f2e2 100644
--- a/src/cron/isolated-agent.turn-test-helpers.ts
+++ b/src/cron/isolated-agent.turn-test-helpers.ts
@@ -60,7 +60,10 @@ export function expectEmbeddedProviderModel(expected: { provider: string; model:
 
 export async function readSessionEntry(storePath: string, key: string) {
   const raw = await fs.readFile(storePath, "utf-8");
-  const store = JSON.parse(raw) as Record<string, { sessionId?: string; label?: string }>;
+  const store = JSON.parse(raw) as Record<
+    string,
+    { sessionId?: string; label?: string; sessionFile?: string }
+  >;
   return store[key];
 }
 
diff --git a/src/cron/isolated-agent/run-executor.ts b/src/cron/isolated-agent/run-executor.ts
index 625fa73d1a1..172aa2f2d01 100644
--- a/src/cron/isolated-agent/run-executor.ts
+++ b/src/cron/isolated-agent/run-executor.ts
@@ -67,10 +67,13 @@ export function createCronPromptExecutor(params: {
   abortSignal?: AbortSignal;
   abortReason: () => string;
 }) {
-  const sessionFile = resolveSessionTranscriptPath(
-    params.cronSession.sessionEntry.sessionId,
-    params.agentId,
-  );
+  const sessionFile =
+    params.cronSession.sessionEntry.sessionFile?.trim() ||
+    resolveSessionTranscriptPath(params.cronSession.sessionEntry.sessionId, params.agentId);
+  // Fallback for callers that bypass prepareCronRunContext before persisting retries.
+  if (!params.cronSession.sessionEntry.sessionFile?.trim()) {
+    params.cronSession.sessionEntry.sessionFile = sessionFile;
+  }
   const cronFallbacksOverride = resolveCronFallbacksOverride({
     cfg: params.cfg,
     job: params.job,
diff --git a/src/cron/isolated-agent/run.ts b/src/cron/isolated-agent/run.ts
index 593a9a94b83..bba5adbd9d8 100644
--- a/src/cron/isolated-agent/run.ts
+++ b/src/cron/isolated-agent/run.ts
@@ -18,6 +18,7 @@ import {
 } from "./helpers.js";
 import { resolveCronModelSelection } from "./model-selection.js";
 import { buildCronAgentDefaultsConfig } from "./run-config.js";
+import { resolveSessionTranscriptPath } from "./run-execution.runtime.js";
 import { executeCronRun, type CronExecutionResult } from "./run-executor.js";
 import {
   createPersistCronSessionEntry,
@@ -272,6 +273,9 @@ async function prepareCronRunContext(params: {
     forceNew: input.job.sessionTarget === "isolated",
   });
   const runSessionId = cronSession.sessionEntry.sessionId;
+  if (!cronSession.sessionEntry.sessionFile?.trim()) {
+    cronSession.sessionEntry.sessionFile = resolveSessionTranscriptPath(runSessionId, agentId);
+  }
   const runSessionKey = baseSessionKey.startsWith("cron:")
     ? `${agentSessionKey}:run:${runSessionId}`
     : agentSessionKey;
diff --git a/src/cron/isolated-agent/session.test.ts b/src/cron/isolated-agent/session.test.ts
index f52c0bd3923..8b050ce53b4 100644
--- a/src/cron/isolated-agent/session.test.ts
+++ b/src/cron/isolated-agent/session.test.ts
@@ -167,6 +167,24 @@ describe("resolveCronSession", () => {
       expect(clearBootstrapSnapshot).toHaveBeenCalledWith("webhook:stable-key");
     });
 
+    it("clears stale sessionFile when forceNew rolls to a fresh session", () => {
+      const result = resolveWithStoredEntry({
+        entry: {
+          sessionId: "existing-session-id-456",
+          updatedAt: NOW_MS - 1000,
+          sessionFile: "/tmp/stale-session.jsonl",
+          modelOverride: "sonnet-4",
+        },
+        fresh: true,
+        forceNew: true,
+      });
+
+      expect(result.sessionEntry.sessionId).not.toBe("existing-session-id-456");
+      expect(result.isNewSession).toBe(true);
+      expect(result.sessionEntry.sessionFile).toBeUndefined();
+      expect(result.sessionEntry.modelOverride).toBe("sonnet-4");
+    });
+
     it("clears delivery routing metadata and deliveryContext when forceNew is true", () => {
       const result = resolveWithStoredEntry({
         entry: {
diff --git a/src/cron/isolated-agent/session.ts b/src/cron/isolated-agent/session.ts
index ae20dfdab20..da33148943c 100644
--- a/src/cron/isolated-agent/session.ts
+++ b/src/cron/isolated-agent/session.ts
@@ -83,6 +83,7 @@ export function resolveCronSession(params: {
       lastAccountId: undefined,
       lastThreadId: undefined,
       deliveryContext: undefined,
+      sessionFile: undefined,
     }),
   };
   return { storePath, store, sessionEntry, systemSent, isNewSession };