So, fairly certain this has worked before but get this when I try to do a trace over IPv6 now:

root@c1841:~# mylg trace google.com -6
trace route to google.com (2a00:1450:400e:801::200e), 30 hops max
invalid argument

Built with go 1.7.3 on Ubuntu 16.04. Works without a glitch over IPv4 and also works with -6 if I run with -u.