only v6 seem not working [3.0.2 nuget]

[uponatime2019]

I have vps with both ipv4 and ipv6, but seem when set v6 only, it's still use ipv4 for download

my code

   listenEndpoints = new Dictionary<string, IPEndPoint>
                            { { "ipv6", new IPEndPoint(IPAddress.IPv6Any, MySettings.Data.TorrentPort) } };
                settingBuilder.ListenEndPoints = listenEndpoints;

count v4 and v6 connection

private int countV4 = 0;
        private int countV6 = 0;
        private readonly HashSet<string> activePeers = new HashSet<string>();

        void AddConnectionTypeCount(TorrentManager manager)
        {
            manager.PeerConnected += (o1, e1) =>
            {
                string peerAddress = e1.Peer.Uri.ToString();

                lock (activePeers)
                {
                    if (!activePeers.Contains(peerAddress))
                    {
                        activePeers.Add(peerAddress);

                        if (e1.Peer.Uri.HostNameType == UriHostNameType.IPv4)
                        {
                            countV4++;
                        }
                        else if (e1.Peer.Uri.HostNameType == UriHostNameType.IPv6)
                        {
                            countV6++;
                        }
                    }
                }
            };

            manager.PeerDisconnected += (o1, e1) =>
            {
                string peerAddress = e1.Peer.Uri.ToString();

                lock (activePeers)
                {
                    if (activePeers.Contains(peerAddress))
                    {
                        activePeers.Remove(peerAddress);

                        if (e1.Peer.Uri.HostNameType == UriHostNameType.IPv4 && countV4 > 0)
                        {
                            countV4--;
                        }
                        else if (e1.Peer.Uri.HostNameType == UriHostNameType.IPv6 && countV6 > 0)
                        {
                            countV6--;
                        }
                    }
                }
            };
        }

Result: v6 usually = 0, v4 count > 0