diff --git a/packages/bots/signal/src/index.ts b/packages/bots/signal/src/index.ts
index a9bec189..8a28777f 100644
--- a/packages/bots/signal/src/index.ts
+++ b/packages/bots/signal/src/index.ts
@@ -24,7 +24,7 @@ export interface IncomingMessage {
   sourceName: string;
   text: string;
   timestamp: number;
-  groupId: string | null;
+  groupId: string | null | undefined;
   isGroup: boolean;
   attachments: Array<{ filename: string; url: string }>;
 }
diff --git a/packages/bots/telegram/src/index.test.ts b/packages/bots/telegram/src/index.test.ts
index 2ee0657c..90481170 100644
--- a/packages/bots/telegram/src/index.test.ts
+++ b/packages/bots/telegram/src/index.test.ts
@@ -4,6 +4,21 @@ import bot, { loadConfig, parseTelegramChatId, toBotEvent } from './index.js';
 
 contractTestBot(bot, { sampleConfig: {}, sampleChannel: '1234567890' });
 
+describe('toBotEvent', () => {
+  it('falls back when Telegram provides an out-of-range timestamp', () => {
+    expect(toBotEvent({
+      source: 'user-1',
+      sourceName: 'User',
+      text: 'hello',
+      timestamp: Number.NaN,
+      chatId: 123,
+      isGroup: false,
+      attachments: [],
+      raw: null as never,
+    }).timestamp).toBe('1970-01-01T00:00:00.000Z');
+  });
+});
+
 describe('parseTelegramChatId', () => {
   it('accepts positive user and negative group chat ids', () => {
     expect(parseTelegramChatId('1234567890')).toBe(1234567890);