It's plausible your antivirus or firewall might inadvertently block NordVPN, halting the VPN from forming a protective tunnel unless NordVPN gets listed as an exception. Automatic updates might instigate a reboot minus VPN safeguards. Yet on a rare occasion, NordVPN itself might be the culprit, like the singular instance where construction cut a cable causing disconnections, rendering the Kill Switch essential during that time.