TUI duplicates rendered text in scrollback on long sessions (Windows + Linux)

Bug: TUI duplicates rendered text as scrollback grows (both Windows + Linux)

Version: Claude Code 2.1.119
Platforms reproduced:

• Windows 10 Pro 19045 — Windows Terminal + Git Bash
• Linux (terminal emulator)

Symptoms:
After a session runs long (~300k+ tokens, many tool calls), previously-printed output starts duplicating in the scrollback — same assistant message and bash/powershell output appears twice, sometimes offset by a few lines. Makes re-reading prior analysis very hard.

Repro steps:

1. Long-running session with many Bash / PowerShell tool calls that stream output
2. Status line + recap banners (※ recap: ...) redraw
3. Scroll up — previous outputs visible twice

Expected: Each message rendered exactly once in scrollback.

Extra context:

• Happens independently of terminal font (observed with Consolas on Windows and default on Linux)
• Happens with ⏵⏵ bypass permissions on mode enabled
• Recaps enabled (not yet disabled via /config)
• Final assistant message + recap block appears to be the block most often duplicated

Happy to share redacted transcript on request.