Terminal rendering breaks in long conversations - status lines print on new lines instead of updating in place

Description

After a conversation reaches a certain length, Claude Code's terminal rendering breaks - status updates print on new lines instead of updating in place. This causes the "Thinking..." spinner to spam hundreds of lines, making the interface unusable.

Expected Behavior

Status lines like "✳ Infusing... (esc to interrupt · 5s · ↓ 217 tokens · thinking)" should update in place on a single line.

Actual Behavior

Each status update prints on a new line, resulting in output like:

✳ Infusing…  (esc to interrupt · 5s · ↓ 217 tokens · thinking)

✳ Infusing…  (esc to interrupt · 5s · ↓ 217 tokens · thinking)

✶ Infusing…  (esc to interrupt · 5s · ↑ 217 tokens · thinking)

✶ Infusing…  (esc to interrupt · 5s · ↑ 218 tokens · thinking)

This continues for hundreds of lines. Tool status also affected:

⏺ Bash(ls -la ~/.claude/file-history/ | head -20)
  ⎿  Waiting…

⏺ Bash(ls -la ~/.claude/file-history/ | head -20)
  ⎿  Waiting…

⏺ Bash(ls -la ~/.claude/file-history/ | head -20)
  ⎿  Running…

Observations

• Does NOT happen at start of conversation - only after conversation reaches a certain length
• Restarting Claude Code fixes it temporarily (until conversation gets long again)
• Sometimes stops on its own after a while
• Occurs in both iTerm2 and Terminal.app on macOS
• ANSI escape codes for cursor movement appear to stop working

Environment

• Claude Code version: 2.0.76
• OS: macOS (Darwin 24.6.0)
• Terminals tested: iTerm2, Terminal.app (bug occurs in both)

Impact

• Interface becomes unusable - can't see conversation
• Consumes excessive terminal buffer
• Have to restart Claude Code frequently during long sessions