[BUG] Claude Code instance becomes unresponsive when starting additional Claude Code Sessions

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?

OS: MAC OS 26
Claude Code version: 2.0.69 (Claude Code)
Terminal: VS Code integrated terminal
Shell: zsh

Claude Code instances that were previously working become stuck in a "thinking" state or completely unresponsive when a second Claude Code terminal session is started.

Expected Behavior:
The original Claude Code instance should continue processing normally regardless of other Claude code terminal activity.

Actual Behavior:
The original instance becomes stuck—either frozen in a "thinking" state indefinitely or stops responding entirely. The task never completes.
Onset:

Started occurring today (December 13, 2025). Was working correctly prior to this date.

What Should Happen?

Expected Behavior:
The original Claude Code instance should continue processing normally regardless of other terminal activity.

Error Messages/Logs

No Error message, trying to have it pressing escape and trying to have it continue where it left off just brings back the timer showing how long its been stuck.

Steps to Reproduce

Open a terminal and start a Claude Code session
Begin a task that requires processing time
While Claude Code is working, open a new terminal window/tab
Start Claude code session and have it start on a task for you
Return to the original Claude Code session -> see thats its stuck but the timer continues to increase

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.0.67

Claude Code Version

2.0.69

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_