[Samba] Disappearing user name

[Miguel Medalha]

I have a PDC with CentOS + Samba 3.2.7 + LDAP serving a network of 
Windows XP workstations. Everything is working very fast and smooth but 
the following happens:

A user such as "John Smith" with username "john" normally appears as 
"John Smith" under Windows XP, as can be seen when we press the Star 
menu button.
But sometimes a user logs on to the domain and the user name does not 
expand from the login name to the full name.
It also happens that the full name appears and then after a while, on 
the same session, only the login name appears.

The complete name "John Smith" is present in LDAP, both under "cn" and 
"displayName". (I noticed that Windows User Manager creates the full 
name under "cn".)

Everything is working very well but it worries me that this could be a 
sign of a misconfiguration or mis function somewhere.
Any hints?

Thank you.