diff --git a/CHANGELOG.md b/CHANGELOG.md
index c6ee9ff1d93..e0421383603 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ Docs: https://docs.openclaw.ai
 
 ### Fixes
 
+- WhatsApp/DM routing: only update main-session last-route state when DM traffic is bound to the main session, preserving isolated `dmScope` routing. (#24949) Thanks @kevinWangSheng.
 - Providers/OpenRouter: when thinking is explicitly off, avoid injecting `reasoning.effort` so reasoning-required models can use provider defaults instead of failing request validation. (#24863) Thanks @DevSecTim.
 - Status/Pairing recovery: show explicit pairing-approval command hints (including requestId when safe) when gateway probe failures report pairing-required closures. (#24771) Thanks @markmusson.
 - Discord/Threading: recover missing thread parent IDs by refetching thread metadata before resolving parent channel context. (#24897) Thanks @z-x-yang.
diff --git a/src/web/auto-reply/monitor/process-message.inbound-contract.test.ts b/src/web/auto-reply/monitor/process-message.inbound-contract.test.ts
index 0acd4056fc9..8458487d8e9 100644
--- a/src/web/auto-reply/monitor/process-message.inbound-contract.test.ts
+++ b/src/web/auto-reply/monitor/process-message.inbound-contract.test.ts
@@ -84,6 +84,7 @@ vi.mock("../deliver-reply.js", () => ({
   deliverWebReply: deliverWebReplyMock,
 }));
 
+import { updateLastRouteInBackground } from "./last-route.js";
 import { processMessage } from "./process-message.js";
 
 describe("web processMessage inbound contract", () => {
@@ -302,4 +303,58 @@ describe("web processMessage inbound contract", () => {
     const replyOptions = (capturedDispatchParams as any)?.replyOptions;
     expect(replyOptions?.disableBlockStreaming).toBe(true);
   });
+
+  it("updates main last route for DM when session key matches main session key", async () => {
+    const updateLastRouteMock = vi.mocked(updateLastRouteInBackground);
+    updateLastRouteMock.mockClear();
+
+    const args = makeProcessMessageArgs({
+      routeSessionKey: "agent:main:whatsapp:direct:+1000",
+      groupHistoryKey: "+1000",
+      msg: {
+        id: "msg-last-route-1",
+        from: "+1000",
+        to: "+2000",
+        chatType: "direct",
+        body: "hello",
+        senderE164: "+1000",
+      },
+    });
+    args.route = {
+      ...args.route,
+      sessionKey: "agent:main:whatsapp:direct:+1000",
+      mainSessionKey: "agent:main:whatsapp:direct:+1000",
+    };
+
+    await processMessage(args);
+
+    expect(updateLastRouteMock).toHaveBeenCalledTimes(1);
+  });
+
+  it("does not update main last route for isolated DM scope sessions", async () => {
+    const updateLastRouteMock = vi.mocked(updateLastRouteInBackground);
+    updateLastRouteMock.mockClear();
+
+    const args = makeProcessMessageArgs({
+      routeSessionKey: "agent:main:whatsapp:dm:+1000:peer:+3000",
+      groupHistoryKey: "+3000",
+      msg: {
+        id: "msg-last-route-2",
+        from: "+3000",
+        to: "+2000",
+        chatType: "direct",
+        body: "hello",
+        senderE164: "+3000",
+      },
+    });
+    args.route = {
+      ...args.route,
+      sessionKey: "agent:main:whatsapp:dm:+1000:peer:+3000",
+      mainSessionKey: "agent:main:whatsapp:direct:+1000",
+    };
+
+    await processMessage(args);
+
+    expect(updateLastRouteMock).not.toHaveBeenCalled();
+  });
 });