diff --git a/extensions/discord/src/monitor/thread-bindings.lifecycle.test.ts b/extensions/discord/src/monitor/thread-bindings.lifecycle.test.ts
index 843291571d6..60e05db5d48 100644
--- a/extensions/discord/src/monitor/thread-bindings.lifecycle.test.ts
+++ b/extensions/discord/src/monitor/thread-bindings.lifecycle.test.ts
@@ -458,6 +458,62 @@ describe("thread binding lifecycle", () => {
     }
   });
 
+  it("preserves explicit lifecycle windows when rebinding the same thread", async () => {
+    vi.useFakeTimers();
+    try {
+      vi.setSystemTime(new Date("2026-02-20T10:00:00.000Z"));
+      const manager = createThreadBindingManager({
+        accountId: "default",
+        persist: false,
+        enableSweeper: false,
+        idleTimeoutMs: 24 * 60 * 60 * 1000,
+        maxAgeMs: 0,
+      });
+
+      await manager.bindTarget({
+        threadId: "thread-1",
+        channelId: "parent-1",
+        targetKind: "subagent",
+        targetSessionKey: "agent:main:subagent:child",
+        agentId: "main",
+        webhookId: "wh-1",
+        webhookToken: "tok-1",
+      });
+
+      setThreadBindingIdleTimeoutBySessionKey({
+        accountId: "default",
+        targetSessionKey: "agent:main:subagent:child",
+        idleTimeoutMs: 2 * 60 * 60 * 1000,
+      });
+      setThreadBindingMaxAgeBySessionKey({
+        accountId: "default",
+        targetSessionKey: "agent:main:subagent:child",
+        maxAgeMs: 3 * 60 * 60 * 1000,
+      });
+
+      vi.setSystemTime(new Date("2026-02-20T10:30:00.000Z"));
+      const rebound = await manager.bindTarget({
+        threadId: "thread-1",
+        channelId: "parent-1",
+        targetKind: "subagent",
+        targetSessionKey: "agent:main:subagent:child",
+        webhookId: "wh-1",
+        webhookToken: "tok-1",
+      });
+
+      expect(rebound).toMatchObject({
+        idleTimeoutMs: 2 * 60 * 60 * 1000,
+        maxAgeMs: 3 * 60 * 60 * 1000,
+      });
+      expect(requireBinding(manager, "thread-1")).toMatchObject({
+        idleTimeoutMs: 2 * 60 * 60 * 1000,
+        maxAgeMs: 3 * 60 * 60 * 1000,
+      });
+    } finally {
+      vi.useRealTimers();
+    }
+  });
+
   it("keeps binding when idle timeout is disabled per session key", async () => {
     vi.useFakeTimers();
     try {
diff --git a/extensions/discord/src/monitor/thread-bindings.manager.ts b/extensions/discord/src/monitor/thread-bindings.manager.ts
index c8155f86a0f..a2cc0d1db21 100644
--- a/extensions/discord/src/monitor/thread-bindings.manager.ts
+++ b/extensions/discord/src/monitor/thread-bindings.manager.ts
@@ -474,8 +474,9 @@ export function createThreadBindingManager(
           "system",
         boundAt: now,
         lastActivityAt: now,
-        idleTimeoutMs,
-        maxAgeMs,
+        idleTimeoutMs:
+          typeof existing?.idleTimeoutMs === "number" ? existing.idleTimeoutMs : idleTimeoutMs,
+        maxAgeMs: typeof existing?.maxAgeMs === "number" ? existing.maxAgeMs : maxAgeMs,
         metadata:
           bindParams.metadata && typeof bindParams.metadata === "object"
             ? { ...existing?.metadata, ...bindParams.metadata }