diff --git a/CHANGELOG.md b/CHANGELOG.md
index c34663e41..bddc24771 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -234,6 +234,7 @@ Docs: https://docs.openclaw.ai
 - Telegram: unify message-like inbound handling so `message` and `channel_post` share the same dedupe/access/media pipeline and remain behaviorally consistent. (#20591) Thanks @obviyus.
 - Telegram/Agents: gate exec/bash tool-failure warnings behind verbose mode so default Telegram replies stay clean while verbose sessions still surface diagnostics. (#20560) Thanks @obviyus.
 - Telegram/Cron/Heartbeat: honor explicit Telegram topic targets in cron and heartbeat delivery (`<chatId>:topic:<threadId>`) so scheduled sends land in the configured topic instead of the last active thread. (#19367) Thanks @Lukavyi.
+- Telegram/DM routing: prevent DM inbound origin metadata from leaking into main-session `lastRoute` updates and normalize DM `lastRoute.to` to provider-prefixed `telegram:<chatId>`. (#19491) thanks @guirguispierre.
 - Gateway/Daemon: forward `TMPDIR` into installed service environments so macOS LaunchAgent gateway runs can open SQLite temp/journal files reliably instead of failing with `SQLITE_CANTOPEN`. (#20512) Thanks @Clawborn.
 - Agents/Billing: include the active model that produced a billing error in user-facing billing messages (for example, `OpenAI (gpt-5.3)`) across payload, failover, and lifecycle error paths, so users can identify exactly which key needs credits. (#20510) Thanks @echoVic.
 - Gateway/TUI: honor `agents.defaults.blockStreamingDefault` for `chat.send` by removing the hardcoded block-streaming disable override, so replies can use configured block-mode delivery. (#19693) Thanks @neipor.
diff --git a/src/channels/session.test.ts b/src/channels/session.test.ts
new file mode 100644
index 000000000..0be177f85
--- /dev/null
+++ b/src/channels/session.test.ts
@@ -0,0 +1,78 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import type { MsgContext } from "../auto-reply/templating.js";
+
+const recordSessionMetaFromInboundMock = vi.fn((_args?: unknown) => Promise.resolve(undefined));
+const updateLastRouteMock = vi.fn((_args?: unknown) => Promise.resolve(undefined));
+
+vi.mock("../config/sessions.js", () => ({
+  recordSessionMetaFromInbound: (args: unknown) => recordSessionMetaFromInboundMock(args),
+  updateLastRoute: (args: unknown) => updateLastRouteMock(args),
+}));
+
+describe("recordInboundSession", () => {
+  const ctx: MsgContext = {
+    Provider: "telegram",
+    From: "telegram:1234",
+    SessionKey: "agent:main:telegram:1234:thread:42",
+    OriginatingTo: "telegram:1234",
+  };
+
+  beforeEach(() => {
+    recordSessionMetaFromInboundMock.mockClear();
+    updateLastRouteMock.mockClear();
+  });
+
+  it("does not pass ctx when updating a different session key", async () => {
+    const { recordInboundSession } = await import("./session.js");
+
+    await recordInboundSession({
+      storePath: "/tmp/openclaw-session-store.json",
+      sessionKey: "agent:main:telegram:1234:thread:42",
+      ctx,
+      updateLastRoute: {
+        sessionKey: "agent:main:main",
+        channel: "telegram",
+        to: "telegram:1234",
+      },
+      onRecordError: vi.fn(),
+    });
+
+    expect(updateLastRouteMock).toHaveBeenCalledWith(
+      expect.objectContaining({
+        sessionKey: "agent:main:main",
+        ctx: undefined,
+        deliveryContext: expect.objectContaining({
+          channel: "telegram",
+          to: "telegram:1234",
+        }),
+      }),
+    );
+  });
+
+  it("passes ctx when updating the same session key", async () => {
+    const { recordInboundSession } = await import("./session.js");
+
+    await recordInboundSession({
+      storePath: "/tmp/openclaw-session-store.json",
+      sessionKey: "agent:main:telegram:1234:thread:42",
+      ctx,
+      updateLastRoute: {
+        sessionKey: "agent:main:telegram:1234:thread:42",
+        channel: "telegram",
+        to: "telegram:1234",
+      },
+      onRecordError: vi.fn(),
+    });
+
+    expect(updateLastRouteMock).toHaveBeenCalledWith(
+      expect.objectContaining({
+        sessionKey: "agent:main:telegram:1234:thread:42",
+        ctx,
+        deliveryContext: expect.objectContaining({
+          channel: "telegram",
+          to: "telegram:1234",
+        }),
+      }),
+    );
+  });
+});
diff --git a/src/channels/session.ts b/src/channels/session.ts
index 8aeb371db..c2f2433be 100644
--- a/src/channels/session.ts
+++ b/src/channels/session.ts
@@ -45,7 +45,8 @@ export async function recordInboundSession(params: {
       accountId: update.accountId,
       threadId: update.threadId,
     },
-    ctx,
+    // Avoid leaking inbound origin metadata into a different target session.
+    ctx: update.sessionKey === sessionKey ? ctx : undefined,
     groupResolution,
   });
 }
diff --git a/src/telegram/bot-message-context.dm-topic-threadid.test.ts b/src/telegram/bot-message-context.dm-topic-threadid.test.ts
index 54d962141..ba566898d 100644
--- a/src/telegram/bot-message-context.dm-topic-threadid.test.ts
+++ b/src/telegram/bot-message-context.dm-topic-threadid.test.ts
@@ -41,8 +41,9 @@ describe("buildTelegramMessageContext DM topic threadId in deliveryContext (#889
     expect(recordInboundSessionMock).toHaveBeenCalled();
 
     // Check that updateLastRoute includes threadId
-    const updateLastRoute = getUpdateLastRoute() as { threadId?: string } | undefined;
+    const updateLastRoute = getUpdateLastRoute() as { threadId?: string; to?: string } | undefined;
     expect(updateLastRoute).toBeDefined();
+    expect(updateLastRoute?.to).toBe("telegram:1234");
     expect(updateLastRoute?.threadId).toBe("42");
   });
 
@@ -57,8 +58,9 @@ describe("buildTelegramMessageContext DM topic threadId in deliveryContext (#889
     expect(recordInboundSessionMock).toHaveBeenCalled();
 
     // Check that updateLastRoute does NOT include threadId
-    const updateLastRoute = getUpdateLastRoute() as { threadId?: string } | undefined;
+    const updateLastRoute = getUpdateLastRoute() as { threadId?: string; to?: string } | undefined;
     expect(updateLastRoute).toBeDefined();
+    expect(updateLastRoute?.to).toBe("telegram:1234");
     expect(updateLastRoute?.threadId).toBeUndefined();
   });
 
diff --git a/src/telegram/bot-message-context.ts b/src/telegram/bot-message-context.ts
index 312f12f8e..ea32380b1 100644
--- a/src/telegram/bot-message-context.ts
+++ b/src/telegram/bot-message-context.ts
@@ -765,7 +765,7 @@ export const buildTelegramMessageContext = async ({
       ? {
           sessionKey: route.mainSessionKey,
           channel: "telegram",
-          to: String(chatId),
+          to: `telegram:${chatId}`,
           accountId: route.accountId,
           // Preserve DM topic threadId for replies (fixes #8891)
           threadId: dmThreadId != null ? String(dmThreadId) : undefined,