Haven't looked on the legacy protocol yet. Did take a look on v6.
IPv6 routing is taking two different paths. Ignore the bad Chicago PTR.
traceroute to nihprod.cit.nih.gov (2607:f220:404:1001::89bb:192b) from 2001:559:800c:1020:225:90ff:fec2:beef, 30 hops max, 24 byte packets
1 2001:559:800c:1020::1 (2001:559:800c::1) 0.258 ms 0.262 ms 0.177 ms
2 2001:559:0:84::1 (2001:559:0:84::1) 0.437 ms 0.439 ms 0.37 ms
3 ae-19-0-ar04.capitolhghts.md.bad.comcast.net (2001:558:340:27a::2) 0.869 ms 0.931 ms 0.927 ms
4 he-2-0-0-0-cr01.chicago.il.ibone.comcast.net (2001:558:0:f6e2::1) 4.618 ms 2.954 ms 4.663 ms
5 be-10001-cr01.ashburn.va.ibone.comcast.net (2001:558:0:f540::1) 5.459 ms 4.873 ms 4.052 ms
6 he-0-11-0-0-pe07.ashburn.va.ibone.comcast.net (2001:558:0:f8d2::2) 2.626 ms 2.565 ms 2.512 ms
7 ashburn-twt.host.twtelecom.net (2001:4870:4500:20::1) 2.162 ms 2.2 ms 2.161 ms
8 2001:4871:ffff:f000:168:215:53:190 (2001:4871:ffff:f000:168:215:53:190) 26.961 ms 2.742 ms 2.88 ms
9 2001:4870:4002:3::2 (2001:4870:4002:3::2) 4.19 ms 5.054 ms 4.82 ms
traceroute to nihprod.cit.nih.gov (2607:f220:404:1001::89bb:192b) from 2001:559:800c:1020:225:90ff:fec2:beef, 30 hops max, 24 byte packets
1 2001:559:800c:1020::1 (2001:559:800c:1020::1) 0.282 ms 0.23 ms 0.206 ms
2 2001:559:0:84::1 (2001:559:0:84::1) 0.452 ms 0.444 ms 0.383 ms
3 ae-19-0-ar04.whitemarsh.md.bad.comcast.net (2001:558:340:27e::2) 3.176 ms 3.196 ms 3.153 ms
4 he-3-4-0-0-11-cr01.newyork.ny.ibone.comcast.net (2001:558:0:f7ac::1) 7.928 ms 10.455 ms 7.948 ms
5 be-10102-cr02.ashburn.va.ibone.comcast.net (2001:558:0:f546::1) 9.632 ms 10.274 ms 8.359 ms
6 be-10001-cr01.ashburn.va.ibone.comcast.net (2001:558:0:f540::1) 9.755 ms 10.402 ms 7.897 ms
7 he-0-11-0-0-pe07.ashburn.va.ibone.comcast.net (2001:558:0:f8d2::2) 7.907 ms 7.906 ms *
8 ashburn-twt.host.twtelecom.net (2001:4870:4500:20::1) 7.541 ms 19.791 ms 7.506 ms
9 2001:4871:ffff:f000:168:215:53:190 (2001:4871:ffff:f000:168:215:53:190) 8.216 ms 8.212 ms 8.256 ms
10 2001:4870:4002:3::2 (2001:4870:4002:3::2) 10.217 ms 9.614 ms 9.743 ms
Somewhat unrelated, nih.gov is not honoring path mtu discovery. Looks like they have a lower MTU (1460) and are filtering ICMP type 2 (packet too big).
# ping6 -s 1453 2607:f220:404:1001::89bb:192b
PING 2607:f220:404:1001::89bb:192b(2607:f220:404:1001::89bb:192b) 1453 data bytes
^C
--- 2607:f220:404:1001::89bb:192b ping statistics ---
29 packets transmitted, 0 received, 100% packet loss, time 28223ms
~# ping6 -s 1453 2001:4870:4002:3::2
PING 2001:4870:4002:3::2(2001:4870:4002:3::2) 1453 data bytes
^C
--- 2001:4870:4002:3::2 ping statistics ---
2 packets transmitted, 0 received, 100% packet loss, time 1008ms
# ping6 -s 1452 2001:4870:4002:3::2
PING 2001:4870:4002:3::2(2001:4870:4002:3::2) 1452 data bytes
1460 bytes from 2001:4870:4002:3::2: icmp_seq=1 ttl=54 time=4.65 ms
1460 bytes from 2001:4870:4002:3::2: icmp_seq=2 ttl=54 time=4.42 ms
^C
--- 2001:4870:4002:3::2 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 4.422/4.536/4.650/0.114 ms