wbinfo --sid-to-name returns different outputs, depending on what has
been queried and cached previously:

$ bin/wbinfo --name-to-sid="$REALM/$DC_USERNAME"
S-1-5-21-274866641-1785003985-1147516049-500 SID_USER (1)

$ bin/wbinfo --sid-to-name=S-1-5-21-274866641-1785003985-1147516049-500
ADDOM.SAMBA.EXAMPLE.COM/administrator 1

$ bin/net cache -s $SERVERCONFFILE flush

$ bin/wbinfo --sid-to-name=S-1-5-21-274866641-1785003985-1147516049-500
ADDOMAIN/Administrator 1

Internall, winbindd issues a LSA lookupnames call that takes the
realm.com\username as input (which is valid according to 3.1.4.5
LsarLookupNames4 (Opnum 77)). The lookupnames call also returns domain
information, including the short domain name. The problem here is that
winbindd fills the cache based on the input from wbinfo, instead of
the domain name queried from the domain controller.

Patches to follow.