Extension crashes Cinnamon on startup, causes all input devices to become floating slaves

[brighttrinity03-lab]

OS: LMDE (Linux Mint Debian Edition
Cinnamon Version: 6.6.7
What happened: On boot, Cinnamon crashed silently with the extension enabled. Desktop loaded but all input devices (keyboard, touchpad, trackpoint) were unresponsive. xinput list showed all devices as floating slaves rather than attached to master pointer/keyboard.
What I expected: Normal desktop with working input
How I confirmed it was this extension: Disabled all extensions via gsettings set org.cinnamon enabled-extensions "[]", re-enabled one by one, confirmed New Window Settings was the culprit.
Relevant errors: Cinnamon just crashed — running in fallback mode dialog on manual restart

[klangman]

Can you attach a copy of your ~/.xsessions-errors file after the error occurs? I am hoping to see some error messages that might help me understand what went wrong.