[BUG] Cannot press Enter in new chats - React error #418 (old chats work fine)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When I try to press Enter in new chats, it doesn't work. Old chats work fine.

Occurs in both regular and incognito mode on different browsers.

Browser console shows React error #418 on page load and ERR_BLOCKED_BY_CLIENT for statsig.anthropic.com

What Should Happen?

Pressing Enter in new chats should submit the message and work the same as in old chats

Error Messages/Logs

React error #418 on page load
ERR_BLOCKED_BY_CLIENT for statsig.anthropic.com

Steps to Reproduce

1. Open Claude Code
2. Start a new chat
3. Type a message
4. Press Enter key
5. Observe that nothing happens - the message is not submitted

Note: This happens in both regular and incognito mode. Old chats work fine.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Web Interface (claude.ai/code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

This issue occurs specifically in the web interface at claude.ai/code, not in any CLI tool.

Browser: Chrome on macOS, Comet on macOS, Safari on macOS
Observed behavior: Enter key is completely unresponsive in new chat sessions, but works normally in existing/old chat sessions.