samba - Nov 2002 - 2.2.7 string overflow in

Hi, 

today I update my "old" samba (2.2.5) to the actuell version. 
After this I found follow error in my logs:
[2002/11/22 08:02:53, 0] lib/util_str.c:string_sub(1219)
  ERROR: string overflow by 4 in string_sub(%u, 7)

After I change 
"logon script = %u.cmd"
to
"logon script=%U.cmd"
samba runs fine.

Could it be a little bug/feature?

Carsten