TLDR: Lawsuit alleges NordVPN's parent company is employing botnet code that is patented by Luminati. Article author suspects that if NordVPN is doing it, it is probably in the vehicle of their VPN app.

It seems to me that suspicious users can avoid this by either connecting to NordVPN VPN proxies using a client they trust rather than through the app. Alternatively, for those on macOS, use the version of the app published in the Mac app store.