duplicate kdc settings in krb5.conf

[Wang Weijun]

My main krb5.conf is

 include /etc/u
 [libdefaults]
 default_realm = D1.LOCAL

 [realms]
 D1.LOCAL = {
   kdc = kdc1
 }

and /etc/u is

 [realms]
 D1.LOCAL = {
   kdc = kdc2
 }

and kinit uses kdc2 as the KDC.

The same is observed if I just include the content of /etc/u inside krb5.conf.

Why is it designed this way? Shouldn't the latecomer override the old one? Or, nobody should ever write this (or these) files so this is just a "undefined" behavior?

Thanks
Max