Confirmed, traceroute from my machine:

{{{
traceroute to repos.fedorapeople.org (2610:28:3090:3001:5054:ff:fedb:7f5a), 30 hops max, 80 byte packets
1 vl-134.er0.fra4.de.rh-tec.net (2001:1a50::61) [AS25560] 0.484 ms 0.502 ms 0.557 ms
2 vl-5.cr0.fra2.de.rh-tec.net (2001:1a50:ffff:fffe::71) [AS25560] 0.565 ms 0.640 ms 0.732 ms
3 vl-300.cr0.fra3.de.rh-tec.net (2001:1a50:ffff:fffe::1) [AS25560] 0.755 ms 0.822 ms 0.883 ms
4 30gigabitethernet4-3.core1.fra1.he.net (2001:7f8::1b1b:0:1) [AS6695] 11.623 ms 1.669 ms 12.392 ms
5 10gigabitethernet1-4.core1.par2.he.net (2001:470:0:1d4::2) [AS6939] 15.811 ms 15.692 ms 15.661 ms
6 10gigabitethernet7-1.core1.ash1.he.net (2001:470:0:1b1::1) [AS6939] 91.132 ms 93.534 ms 95.629 ms
7 2001:470:0:227::2 (2001:470:0:227::2) [AS6939] 93.163 ms 93.059 ms 92.993 ms
8 2001:468:ff:9c5::2 (2001:468:ff:9c5::2) [] 102.165 ms 102.117 ms 102.096 ms
9 2610:28:105:3::2 (2610:28:105:3::2) [] 96.488 ms 96.432 ms 96.867 ms
10 unc-to-rlgh7600-gw.ncren.net (2610:28:104:6::2) [] 101.431 ms 101.386 ms 101.887 ms
11 2610:28:3090:13::2 (2610:28:3090:13::2) [] 98.847 ms 98.272 ms 101.334 ms
12 * * *
13 * * *
14 * * *
15 * * *
}}}

From my point of view, the IPv6 address has simply not been set up on people03.fedoraproject.org:

{{{
[robert@people03 ~]$ ip addr list
1: lo: mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: mtu 1280 qdisc pfifo_fast state UP qlen 1000
link/ether 52:54:00:db:7f:5a brd ff:ff:ff:ff:ff:ff
inet 152.19.134.191/25 brd 152.19.134.255 scope global eth0
inet6 fe80::5054:ff:fedb:7f5a/64 scope link
valid_lft forever preferred_lft forever
3: tun0: mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 100
link/[65534]
inet 192.168.100.3/32 scope global tun0
[robert@people03 ~]$
}}}

Hope this helps the admins to track this down more easily...

Fixed.

The host somehow just decided to drop it's ipv6 address. I restarted things and everything seems back up now.