traceroute6 doesn't display the target's fqdn properly

[pierre]

traceroute (ipv4) displays the FQDN and the IP of the host it is about to trace:

$ traceroute free.fr
traceroute to free.fr (212.27.48.10), 30 hops max, 60 byte packets

$ traceroute comcast6.net
traceroute to comcast6.net (69.252.80.75), 30 hops max, 60 byte packets

traceroute 6 does the same thing, but can't display the FQDN properly:

$ traceroute6 free.fr
traceroute to @D}HsU (2a01:e0c:1::1) from <snip>, 30 hops max, 24 byte packets

$ traceroute6 comcast6.net
traceroute to P����U (2001:558:feed:1:69:252:80:75) from <snip>7, 30 hops max, 24 byte packets

Instead of the garbled text before the IPv6, it should display the FQDN, just like it does for IPv4.

These are the versions I have on mad64 (didn't try other architectures):

$ traceroute --version
Modern traceroute for Linux, version 2.1.0
Copyright (c) 2016 Dmitry Butskoy, License: GPL v2 or any later

$ traceroute6 -V
traceroute6 utility, iputils-s20161105

$ lsb_release -rd
Description: Ubuntu 17.10
Release: 17.10

$ sudo apt-cache policy inetutils-traceroute
inetutils-traceroute:
  Installed: (none)
  Candidate: 2:1.9.4-2build1
  Version table:
     2:1.9.4-2build1 500
        500 http://ca.archive.ubuntu.com/ubuntu artful/universe amd64 Packages