Ok turns out I can be dumb too

examples/chat-ui/src/hooks/useStreamResponse.ts

@@ -327,7 +327,7 @@ export const useStreamResponse = ({
           if (updatedMessage || newMessage) {
             updated = prev.map((c) => {
               if (c.id !== conversationId) return c
-              const messages = c.messages
+              let messages = [...c.messages]
 
               if (updatedMessage) {
                 messages.splice(-1, 1, updatedMessage)

examples/chat-ui/src/main.tsx

@@ -3,8 +3,14 @@ import { createRoot } from 'react-dom/client'
 import './index.css'
 import App from './App.tsx'
 
+const ENABLE_STRICT_MODE = true
+
 createRoot(document.getElementById('root')!).render(
-  <StrictMode>
+  ENABLE_STRICT_MODE ? (
+    <StrictMode>
+      <App />
+    </StrictMode>
+  ) : (
     <App />
-  </StrictMode>
+  )
 )