diff --git a/CHANGELOG.md b/CHANGELOG.md
index 04248fe0d4a..38a1a2b5014 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -320,6 +320,7 @@ Docs: https://docs.openclaw.ai
 - Exec approvals/config fallback: inherit `ask` from `exec-approvals.json` when `tools.exec.ask` is unset, so local full/off defaults no longer fall back to `on-miss` for exec tool and `nodes run`. Landed from contributor PR #29187 by @Bartok9. Thanks @Bartok9.
 - Exec approvals/allow-always shell scripts: persist and match script paths for wrapper invocations like `bash scripts/foo.sh` while still blocking `-c`/`-s` wrapper bypasses. Landed from contributor PR #35137 by @yuweuii. Thanks @yuweuii.
 - Queue/followup dedupe across drain restarts: dedupe queued redelivery `message_id` values after queue recreation so busy-session followups no longer duplicate on replayed inbound events. Landed from contributor PR #33168 by @rylena. Thanks @rylena.
+- Telegram/preview-final edit idempotence: treat `message is not modified` errors during preview finalization as delivered so partial-stream final replies do not fall back to duplicate sends. Landed from contributor PR #34983 by @HOYALIM. Thanks @HOYALIM.
 
 ## 2026.3.2
 
diff --git a/src/telegram/lane-delivery.test.ts b/src/telegram/lane-delivery.test.ts
index 5259a99f6c7..1cd1d36cf4c 100644
--- a/src/telegram/lane-delivery.test.ts
+++ b/src/telegram/lane-delivery.test.ts
@@ -146,6 +146,30 @@ describe("createLaneTextDeliverer", () => {
     expect(harness.log).toHaveBeenCalledWith(expect.stringContaining("treating as delivered"));
   });
 
+  it("treats 'message is not modified' preview edit errors as delivered", async () => {
+    const harness = createHarness({ answerMessageId: 999 });
+    harness.editPreview.mockRejectedValue(
+      new Error(
+        "400: Bad Request: message is not modified: specified new message content and reply markup are exactly the same as a current content and reply markup of the message",
+      ),
+    );
+
+    const result = await harness.deliverLaneText({
+      laneName: "answer",
+      text: "Hello final",
+      payload: { text: "Hello final" },
+      infoKind: "final",
+    });
+
+    expect(result).toBe("preview-finalized");
+    expect(harness.editPreview).toHaveBeenCalledTimes(1);
+    expect(harness.sendPayload).not.toHaveBeenCalled();
+    expect(harness.markDelivered).toHaveBeenCalledTimes(1);
+    expect(harness.log).toHaveBeenCalledWith(
+      expect.stringContaining('edit returned "message is not modified"; treating as delivered'),
+    );
+  });
+
   it("falls back to normal delivery when editing an existing preview fails", async () => {
     const harness = createHarness({ answerMessageId: 999 });
     harness.editPreview.mockRejectedValue(new Error("500: preview edit failed"));
diff --git a/src/telegram/lane-delivery.ts b/src/telegram/lane-delivery.ts
index b02837d90b0..d46fd66cf57 100644
--- a/src/telegram/lane-delivery.ts
+++ b/src/telegram/lane-delivery.ts
@@ -2,6 +2,23 @@ import type { ReplyPayload } from "../auto-reply/types.js";
 import type { TelegramInlineButtons } from "./button-types.js";
 import type { TelegramDraftStream } from "./draft-stream.js";
 
+const MESSAGE_NOT_MODIFIED_RE =
+  /400:\s*Bad Request:\s*message is not modified|MESSAGE_NOT_MODIFIED/i;
+
+function isMessageNotModifiedError(err: unknown): boolean {
+  const text =
+    typeof err === "string"
+      ? err
+      : err instanceof Error
+        ? err.message
+        : typeof err === "object" && err && "description" in err
+          ? typeof err.description === "string"
+            ? err.description
+            : ""
+          : "";
+  return MESSAGE_NOT_MODIFIED_RE.test(text);
+}
+
 export type LaneName = "answer" | "reasoning";
 
 export type DraftLaneState = {
@@ -216,6 +233,13 @@ export function createLaneTextDeliverer(params: CreateLaneTextDelivererParams) {
       params.markDelivered();
       return true;
     } catch (err) {
+      if (isMessageNotModifiedError(err)) {
+        params.log(
+          `telegram: ${args.laneName} preview ${args.context} edit returned "message is not modified"; treating as delivered`,
+        );
+        params.markDelivered();
+        return true;
+      }
       if (args.treatEditFailureAsDelivered) {
         params.log(
           `telegram: ${args.laneName} preview ${args.context} edit failed after stop-created flush; treating as delivered (${String(err)})`,