[BUG] Input Delay & Cursor Misplacement in Claude CLI on Ubuntu 22.04

Environment

• Platform (select one):
• [ ] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [x] Other: Claude CLI
• Claude CLI version: 1.0.40
• Operating System: Ubuntu 22.04 LTS
• Terminal: GNOME Terminal (default Ubuntu terminal)

Bug Description

When typing a prompt in Claude Code within the standard Ubuntu 22.04 terminal, input is subject to intermittent delays: characters appear in large batches instead of instantly. Deleting characters causes the cursor to move beyond the visible text, and repeated Backspace presses move the cursor over empty space instead of deleting characters.

Steps to Reproduce

1. Open the default GNOME Terminal on Ubuntu 22.04.
2. Run claude code and type text quickly.
3. Press Backspace to delete text.

Expected Behavior

Each character should appear immediately as it’s typed without any noticeable delay. Backspace should consistently delete the character before the cursor and keep the cursor within the text.

Actual Behavior

Characters are "buffered" and displayed in batches after a pause of several hundred milliseconds. The cursor moves outside the text when deleting, and Backspace does not remove characters but only moves the cursor around empty space.

Additional Context

• Video demonstration - at the start of the video, each Backspace press moves the caret outside the text.
• Issue does not occur on macOS in the default Terminal or in Warp.

https://github.com/user-attachments/assets/4b0f657c-5c52-4405-bad9-a202c7288b62

Immediately after recording this video, I noticed my Max subscription account was blocked. Currently, even with the account blocked, the CLI and prompt input remain accessible, allowing me to test; no input issues occur when using the locked account.