[BUG] Multiple Claude headers appear when scrolling up in long conversations (macOS terminal)

What's Wrong?

When scrolling up through a long conversation in the macOS terminal app, multiple Claude headers appear and the current conversation renders multiple times. The conversation content duplicates visually as you scroll.

Environment

• OS: macOS
• Terminal: macOS terminal app (not VS Code)
• Claude Code Version: latest

Steps to Reproduce

1. Have a long conversation in Claude Code (macOS terminal)
2. Scroll up through the conversation history
3. Multiple Claude headers appear and the conversation content is rendered more than once

Expected Behavior

Conversation should render once. Scrolling up should show a clean, single history.

Actual Behavior

Multiple Claude headers are visible when scrolling up. The current conversation appears duplicated.

Screen Recording

Screen recording attached — see claude bug.mov

Related Issues

• #15476 (closed/not planned) — duplicate content in VS Code terminal
• #9668 (closed/completed) — duplicate conversation titles (different issue)

This appears to be a distinct rendering bug specific to the macOS terminal app.