VPN client was only started if VPN_ENABLED was "yes". However, earlier in the start.sh file preparations were done whenever VPN_ENABLED was either 1/true/yes. Using a non-string 'yes' value in docker-compose.yaml, for instance, would automatically make VPN_ENABLED take a value of "true", and that would cause the VPN client not to start, without printing any sort of warning or error.