Hi Wheaton, the plugin just serves a web page (the “now playing” screen) to the Chromium browser that’s running on Volumio. The closest “system-level” modification done is to the volumiokiosk.sh script which simply changes http://localhost:3000 to http://localhost:4004 (the address through which the now playing screen is served).
One thing though… when the plugin is activated or deactivated, such as when Volumio starts or shuts down, the volumio-kiosk is restarted. I understand this will also trigger a restart of Xorg. I wonder if upon restarting, the calibration profile failed to load. But then, you said everything is working again after disabling the plugin… did you by any chance reboot Volumio after doing that?