Steps to reproduce:
1. Open Audacity
2. Open new Audacity window via Ctrl+N or Ctrl+O
3. Add new stereo track in both windows (so Audacity will not quit silently)
4. Quit Audacity from the first window (via menu or Ctrl+Q)
5. Select “No” to discard the project for the first window
6. Select “Cancel” to not close for the second window
7. Segfault :|

The issue doesn’t reproduce if one quits Audacity from the second window.

Environment: Arch Linux, Xfce, Audacity 3.7.7