[BUG] Terminal charset corruption (G1 alternate set stuck) after interrupted spinner / escape sequence

Reproducing with a much simpler setup — Claude Code running natively on Windows, no SSH, no remote pod, no RDP/TeamViewer:

• Windows 11
• VS Code integrated terminal (ConPTY)
• PowerShell 7.6.1
• Claude Code 2.1.141

Likely a regression in 2.1.141 — first hit it today, yesterday on 2.1.140 was fine. 2.1.141 shipped 2026-05-13 ~23:19 UTC and this issue was filed ~3 hours later, which lines up.

Same selective corruption — ASCII-only lines and lines that emit their own reset (the "almost done thinking..." spinner text, numbers, 244 px) render fine while the rest of the screen is remapped through the alternate charset. Screenshot attached.

Extra data point: resizing the terminal a few columns fixes the rendering temporarily (presumably the re-layout emits a full clear), but it can come back later in the same session.

Since there's no SSH or remote-control layer here, the bad bytes have to be coming from Claude Code itself — not from intermediate transports mangling the stream.

<img width="1272" height="1919" alt="Image" src="https://github.com/user-attachments/assets/b4b193f0-77bf-41b9-96fa-c9d94a144bb3" />

Hitting what looks like the same root cause on a different platform/terminal combo — adding here rather than filing a duplicate, since it strengthens the "stuck terminal state" diagnosis.

Environment

• Claude Code: 2.1.141
• Terminal: VS Code integrated terminal (xterm.js), not a native terminal
• OS: macOS (Darwin 24.6.0), MacBook Air M4
• $TERM: xterm-256color
• No project-level .claude/ hooks or statusline customizations

Symptom variant
Instead of G1 alternate charset, the terminal renders text with combining diacritical marks (mostly combining dot above, U+0307) overlaid on letters, with the base letter sometimes replaced. Examples from one session:

• logger → kogger
• POST → hOST
• finishing → kinishing
• captureMessage → captureTessage
• exporter → ixporter

Same diagnostic signals as the original report

• Session rendered cleanly for ~30 minutes, then degraded and stayed degraded
• Affects all output sources after onset (tool results, assistant text, spinner) — not just one tool's output
• Underlying conversation/state intact — corruption is purely render-layer
• Highlighting text with the cursor to copy actively changes which characters are corrupted in real time — strong signal the cell buffer is being re-rendered with non-deterministic glyph placement on each repaint
• Session involved long streaming outputs (curl piped to python printing Sentry event payloads), consistent with the "interrupted spinner during event burst" trigger hypothesis

Why this matters for the fix
Suggests the underlying class is broader than "G1 charset stuck" — any terminal state that's mode-sensitive (alternate charsets, combining-mark composition modes in xterm.js, etc.) can get stuck the same way if Claude Code's TUI doesn't defensively reset state on spinner-cleanup and signal-handler paths. The proposed fix (emit \017\e[0m on every exit/cleanup path) would address both variants.

<img width="1412" height="318" alt="Image" src="https://github.com/user-attachments/assets/2a16e7ef-38d2-4ad2-af2a-0f05301c2bd4" />

I am getting the same in Windsurf, it is corrupting all my other terminal windows.

<img width="880" height="385" alt="Image" src="https://github.com/user-attachments/assets/1030e317-a9cd-429b-a81d-8c19b0e90a9d" />
<img width="848" height="417" alt="Image" src="https://github.com/user-attachments/assets/9dc49741-82ea-4ec0-838b-f63ebaf65922" />

Confirming the regression range and a working downgrade path.

I was hitting this consistently on 2.1.143 (Windows 11, VS Code integrated terminal, pwsh 7.6.1, ConPTY) — no improvement on 2.1.141 → 2.1.142 → 2.1.143.

Downgrading to 2.1.140 stops the corruption entirely. The native installer has a built-in version subcommand:

claude install 2.1.140 --force

Then pin it so the auto-updater doesn't silently bump you back:

// ~/.claude/settings.json
{
  "env": {
    "DISABLE_UPDATES": "1",
    "DISABLE_AUTOUPDATER": "1"
  }
}

Been running on 2.1.140 for a while now — zero corruption events. So the affected range is 2.1.141 → 2.1.143 inclusive (every release since this issue was filed).

Two 2.1.141 changelog entries touch the rendering area and look like reasonable starting points for the diff:

Improved spinner feedback during long thinking periods — the spinner now warms to amber after 10 seconds to signal Claude is still working

Fixed multi-line statusline output dropping or corrupting rows when any line exceeds terminal width

Pinning to 2.1.140 in the meantime.

---

Update (2026-05-20): still reproduces on 2.1.145, same setup. 2.1.145 carries the 2.1.144 terminal-rendering fixes, so those do not address this:

Fixed garbled terminal output after a missed window-resize event (e.g. dragging a VS Code split-pane divider) — now self-heals on the next frame instead of requiring Ctrl+L

Fixed progressive terminal display corruption (stale/garbled glyphs) that could appear in very long sessions and only cleared on terminal resize or restart

Rolled back to 2.1.140 again — still the only clean version.

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.