Random blue characters appearing in terminal output (Windows Terminal)

Description

Random characters in Claude Code's output appear in blue, seemingly without pattern or reason. The affected characters change each time, even for identical output.

Screenshots

!Blue characters example

(Visual: random letters like "t" in "list", "s" in "shows", parts of "--all won't touch it", "d" in "behind" appear blue while surrounding text is normal)

Environment

• OS: Windows 11
• Terminal: Windows Terminal
• Claude Code version: Latest

Observations

• Happens frequently, not every time
• Pattern appears random — different characters affected each run
• Not related to terminal search/find feature
• Not related to Windows Terminal URL auto-detection
• Purely cosmetic but visually distracting

Likely cause

Possibly malformed or unclosed ANSI escape sequences bleeding into unintended parts of the output.

Steps to reproduce

1. Use Claude Code in Windows Terminal
2. Have a multi-paragraph response generated
3. Observe random characters highlighted in blue