Dns.GetHostAddresses only returns one address in mono

gistfile1.txt

robert@fotnmc:~/code/BitcoinFs$ nslookup seed.bitcoin.sipa.be
Server:		127.0.0.1
Address:	127.0.0.1#53

Non-authoritative answer:
Name:	seed.bitcoin.sipa.be
Address: 71.172.136.155
Name:	seed.bitcoin.sipa.be
Address: 108.183.38.208
Name:	seed.bitcoin.sipa.be
Address: 24.10.174.166
Name:	seed.bitcoin.sipa.be
Address: 96.32.8.13
Name:	seed.bitcoin.sipa.be
Address: 217.42.250.168
Name:	seed.bitcoin.sipa.be
Address: 185.10.56.105
Name:	seed.bitcoin.sipa.be
Address: 148.251.67.240
Name:	seed.bitcoin.sipa.be
Address: 110.77.137.88
Name:	seed.bitcoin.sipa.be
Address: 159.253.96.225
Name:	seed.bitcoin.sipa.be
Address: 173.68.90.123
Name:	seed.bitcoin.sipa.be
Address: 98.195.174.110
Name:	seed.bitcoin.sipa.be
Address: 134.249.172.211
Name:	seed.bitcoin.sipa.be
Address: 158.255.89.244
Name:	seed.bitcoin.sipa.be
Address: 100.0.178.206
Name:	seed.bitcoin.sipa.be
Address: 108.45.183.71
Name:	seed.bitcoin.sipa.be
Address: 81.5.87.199
Name:	seed.bitcoin.sipa.be
Address: 110.146.182.8
Name:	seed.bitcoin.sipa.be
Address: 188.61.136.196
Name:	seed.bitcoin.sipa.be
Address: 91.121.197.189
Name:	seed.bitcoin.sipa.be
Address: 78.140.52.90
Name:	seed.bitcoin.sipa.be
Address: 89.2.255.141
Name:	seed.bitcoin.sipa.be
Address: 5.9.13.20
Name:	seed.bitcoin.sipa.be
Address: 72.78.245.76
Name:	seed.bitcoin.sipa.be
Address: 86.130.188.69
Name:	seed.bitcoin.sipa.be
Address: 67.169.80.163
Name:	seed.bitcoin.sipa.be
Address: 98.166.213.17
Name:	seed.bitcoin.sipa.be
Address: 68.69.167.41
Name:	seed.bitcoin.sipa.be
Address: 23.114.202.100

robert@fotnmc:~/code/BitcoinFs$ fsharpi

F# Interactive for F# 3.1 (Open Source Edition)
Freely distributed under the Apache 2.0 Open Source License

For help type #help;;

> open System.Net;;
> Dns.GetHostAddresses("seed.bitcoin.sipa.be");;
val it : IPAddress [] = [|67.163.160.108 {Address = 1822466883L;
                                          AddressFamily = InterNetwork;
                                          IsIPv6LinkLocal = false;
                                          IsIPv6Multicast = false;
                                          IsIPv6SiteLocal = false;
                                          IsIPv6Teredo = false;
                                          ScopeId = ?;}|]
> #q;;