diff --git a/src/whatsapp/manager.mjs b/src/whatsapp/manager.mjs
index 861277f..f90e250 100644
--- a/src/whatsapp/manager.mjs
+++ b/src/whatsapp/manager.mjs
@@ -46,6 +46,7 @@ function withTimeout(promise, timeoutMs, createError) {
   const provider = Promise.resolve(promise);
   const timeout = new Promise((_, reject) => {
     timer = setTimeout(() => reject(createError()), timeoutMs);
+    timer.unref?.();
   });
   provider.catch(() => {});
   return Promise.race([provider, timeout]).finally(() => clearTimeout(timer));
@@ -101,6 +102,17 @@ export function createWhatsAppManager({
   const pendingMessageStatuses = new Map();
   const messageStatusInFlight = new Map();
   const inboundMessageIds = new Set();
+  // Set nunca esvaziado individualmente (so no disconnect inteiro): sem um
+  // teto, cresce sem limite proporcional ao volume total de mensagens
+  // recebidas ao longo da vida da conexao. Descarta o id mais antigo (Set
+  // preserva ordem de insercao) ao ultrapassar o teto.
+  const MAX_INBOUND_DEDUP_IDS = 5000;
+  const rememberInboundMessageId = (messageId) => {
+    inboundMessageIds.add(messageId);
+    if (inboundMessageIds.size > MAX_INBOUND_DEDUP_IDS) {
+      inboundMessageIds.delete(inboundMessageIds.values().next().value);
+    }
+  };
   const lockPath = path.join(path.dirname(authDir), `${path.basename(authDir)}.lock`);
   const recoveryPath = `${lockPath}.recovery`;
 
@@ -359,7 +371,7 @@ export function createWhatsAppManager({
             const timestampMs = Number.isFinite(rawTimestamp)
               ? rawTimestamp * (rawTimestamp < 1e12 ? 1_000 : 1)
               : Date.now();
-            inboundMessageIds.add(String(messageId));
+            rememberInboundMessageId(String(messageId));
             Promise.resolve().then(() => onInboundMessage({
               messageId: String(messageId),
               jid,
diff --git a/tests/whatsapp-manager.test.mjs b/tests/whatsapp-manager.test.mjs
index c91b484..83958de 100644
--- a/tests/whatsapp-manager.test.mjs
+++ b/tests/whatsapp-manager.test.mjs
@@ -349,6 +349,38 @@ test('messages.upsert publica uma vez somente mensagens inbound novas de convers
   await fs.rm(f.authDir, { recursive: true, force: true });
 });
 
+// O Set de dedup so era esvaziado inteiro no disconnect: sem um teto,
+// crescia sem limite proporcional ao volume total de mensagens recebidas
+// durante a vida da conexao. Envia 1 mensagem a mais que o teto interno
+// (5000) e confirma que a mais antiga foi descartada (tratada como nova de
+// novo), provando que o Set nao cresce indefinidamente.
+test('dedup de mensagens inbound tem teto e descarta a mais antiga', async () => {
+  const inbound = [];
+  const f = await fixture({ onInboundMessage: (event) => inbound.push(event) });
+  await f.manager.connect();
+  const socket = f.sockets[0];
+  socket.ev.emit('connection.update', { connection: 'open' });
+
+  const TOTAL = 5001;
+  for (let i = 0; i < TOTAL; i++) {
+    socket.ev.emit('messages.upsert', {
+      type: 'notify',
+      messages: [{ key: { id: `msg-${i}`, remoteJid: '5575999091780@s.whatsapp.net', fromMe: false }, messageTimestamp: 1785326400 }]
+    });
+  }
+  await waitFor(() => inbound.length === TOTAL, 5000);
+
+  socket.ev.emit('messages.upsert', {
+    type: 'notify',
+    messages: [{ key: { id: 'msg-0', remoteJid: '5575999091780@s.whatsapp.net', fromMe: false }, messageTimestamp: 1785326400 }]
+  });
+  await waitFor(() => inbound.length === TOTAL + 1, 2000);
+  assert.equal(inbound.filter((e) => e.messageId === 'msg-0').length, 2);
+
+  await f.manager.close();
+  await fs.rm(f.authDir, { recursive: true, force: true });
+});
+
 test('falha ao persistir inbound nao escapa do EventEmitter nem gera resposta automatica', async () => {
   const logs = [];
   const f = await fixture({