[BUG] Cursor jumps to end when editing prompt text

Environment

• Platform (select one):
• [ X ] Anthropic API
• [ X ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: 1.0.83
• Operating System: Debian, Windows 10, Windows 11 (WSL2 Ubuntu)
• Terminal: Bash, Git Bash, WSL2 Ubuntu bash

Bug Description

When using arrow keys to position the cursor in the middle of a prompt and then typing any character, the cursor jumps to the end of the prompt after typing a single character.

Steps to Reproduce

1. Start typing a prompt in Claude Code
2. Use arrow keys (left/right) to position cursor in the middle of the text
3. Type any character to edit the prompt
4. Observe cursor behavior (jumps to end after typing single character)

Expected Behavior

The cursor should remain at the positioned location to allowing for normal text editing.

Actual Behavior

After the letter is typed the cursor jumps to the end of the prompt and any subsequent text is added to the end.

Additional Context

Cross platform issue, impacting Linux, Windows, WSL. This suggest it is likely an input handling issue within Claude Code itself rather than environment-specific terminal behavior.