No root cause but found work around.
Even though hosts to be added are fully in /etc/hosts and able to resolve and ssh
passwordless login is fine...
[root@thor ~]# ping odin
PING odin.penguinpages.local (172.16.100.102) 56(84) bytes of data.
64 bytes from odin.penguinpages.local (172.16.100.102): icmp_seq=1 ttl=64 time=0.085 ms
^C
--- odin.penguinpages.local ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.085/0.085/0.085/0.000 ms
[root@thor ~]# ping odin.penguinpages.local
PING odin.penguinpages.local (172.16.100.102) 56(84) bytes of data.
64 bytes from odin.penguinpages.local (172.16.100.102): icmp_seq=1 ttl=64 time=0.083 ms
^C
--- odin.penguinpages.local ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.083/0.083/0.083/0.000 ms
change target system to IP address allows host to be added
Hmm.. my guess is something is hard coded to IP and not right here..
I will post if I find more.