[Bug] Startup header renders multiple times in Windows PowerShell / Terminal (v2.1.119)

Bug Description

The Claude Code startup header (logo, version info, model, working directory) renders multiple times in the terminal on Windows, causing the conversation window to be very cluttered with repeated content. This happens not only at startup but also during normal task execution — previous text/UI blocks reappear and stack up multiple times.

Environment

• OS: Windows 11 Home (Build 10.0.26200)
• Shell: PowerShell (also observed in Windows Terminal)
• Claude Code version: v2.1.119 (latest)
• Node.js: v22.11.0
• npm: v10.9.0

Steps to Reproduce

1. Open PowerShell on Windows 11
2. Run claude
3. Observe the startup header (logo + version + model + directory + separator line) appears multiple times before the prompt
4. During normal usage, the same header block repeats again after responses

Expected Behavior

The startup header should appear once, and the TUI should cleanly re-render without duplicating previous blocks.

Actual Behavior

The header block is duplicated 5–8+ times in the terminal output, making it very difficult to read the conversation. Each duplicate is separated by the status bar line ($0.000 | Context window...).

Error Log (npm update attempt)

npm warn cleanup Failed to remove some directories [
npm warn cleanup   [
npm warn cleanup     'C:\Users\MT2505\AppData\Roaming\npm\node_modules\@anthropic-ai\.claude-code-ULLbAi6p',
npm warn cleanup     [Error: EPERM: operation not permitted, unlink 'C:\Users\MT2505\AppData\Roaming\npm\node_modules\@anthropic-ai\.claude-code-ULLbAi6p\bin\claude.exe'] {
npm warn cleanup       errno: -4048,
npm warn cleanup       code: 'EPERM',
npm warn cleanup       syscall: 'unlink',
npm warn cleanup       path: 'C:\Users\MT2505\AppData\Roaming\npm\node_modules\@anthropic-ai\.claude-code-ULLbAi6p\bin\claude.exe'
npm warn cleanup     }
npm warn cleanup   ]
npm warn cleanup ]

(EPERM is expected since Claude Code was running during update — noted for reference)

Suspected Cause

The TUI rendering framework appears to trigger multiple full re-renders on Windows when:

• Terminal window is resized
• Window focus changes between tabs
• Scroll events occur

Each re-render appends the full header block without clearing the previous one.

Workaround

Using Windows Terminal app instead of raw PowerShell window reduces (but does not eliminate) the frequency of duplicates.

Additional Notes

• This was reported via the Claude Code CLI itself using gh issue create
• Screenshot available showing 5+ repeated header blocks in a single session

/cc @anthropic-ai/claude-code-team