Some guy who has been IP spoofing found another way to annoy players.

Presumably, they are scraping client IPs by hosting a fake server and some time later send "disconnect" messages to these client IPs with spoofed server IP.

Except being just annoying, it doesn't seem to be harmful. But I'm not sure how to fix it. Send current qport as an argument? It will break disconnection from unpatched servers.