I get DUP! message when i ping from FG-310B

Hi, I tried pinging few FQDN' s from the FG console & get DUP! message. Any reason as why i get this message? FG-310B # execute ping www.speechmachines.org PING mq1webc1.speechmachines.org (208.16.209.131): 56 data bytes 64 bytes from 208.16.209.131: icmp_seq=0 ttl=111 time=249.5 ms 64 bytes from 208.16.209.131: icmp_seq=0 ttl=111 time=249.6 ms (DUP!) 64 bytes from 208.16.209.131: icmp_seq=0 ttl=111 time=250.0 ms (DUP!) 64 bytes from 208.16.209.131: icmp_seq=0 ttl=111 time=250.6 ms (DUP!) 64 bytes from 208.16.209.131: icmp_seq=1 ttl=111 time=252.8 ms 64 bytes from 208.16.209.131: icmp_seq=1 ttl=111 time=252.9 ms (DUP!) 64 bytes from 208.16.209.131: icmp_seq=1 ttl=111 time=253.4 ms (DUP!) 64 bytes from 208.16.209.131: icmp_seq=1 ttl=111 time=253.4 ms (DUP!) 64 bytes from 208.16.209.131: icmp_seq=2 ttl=111 time=248.9 ms 64 bytes from 208.16.209.131: icmp_seq=2 ttl=111 time=249.5 ms (DUP!) 64 bytes from 208.16.209.131: icmp_seq=2 ttl=111 time=249.6 ms (DUP!) 64 bytes from 208.16.209.131: icmp_seq=2 ttl=111 time=249.6 ms (DUP!) 64 bytes from 208.16.209.131: icmp_seq=3 ttl=111 time=257.3 ms 64 bytes from 208.16.209.131: icmp_seq=3 ttl=111 time=257.5 ms (DUP!) 64 bytes from 208.16.209.131: icmp_seq=3 ttl=111 time=257.5 ms (DUP!) 64 bytes from 208.16.209.131: icmp_seq=3 ttl=111 time=258.3 ms (DUP!) 64 bytes from 208.16.209.131: icmp_seq=4 ttl=111 time=257.3 ms --- mq1webc1.speechmachines.org ping statistics --- 5 packets transmitted, 5 packets received, 12 duplicates, 0% packet loss round-trip min/avg/max = 248.9/252.8/258.3 ms