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/run-executor.ts b/src/cron/isolated-agent/run-executor.ts
index 9c84e79c351..172aa2f2d01 100644
--- a/src/cron/isolated-agent/run-executor.ts
+++ b/src/cron/isolated-agent/run-executor.ts
@@ -70,6 +70,7 @@ export function createCronPromptExecutor(params: {
   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;
   }
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 };