filename expansion with [a-z] matches upper case

[root]

Configuration Information [Automatically generated, do not change]:
Machine: i386
OS: linux-gnu
Compiler: i386-redhat-linux-gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i386' 
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i386-redhat-linux-gnu' 
-DCONF_VENDOR='redhat' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL 
-DHAVE_CONFIG_H  -I.  -I. -I./include -I./lib  -D_GNU_SOURCE 
-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -O2 -g -pipe -Wp,-D_FORTIFY_SOURCE=2 
-fexceptions -m32 -march=i386 -mtune=pentium4 -fasynchronous-unwind-tables
uname output: Linux mail.samco.com 2.6.11-1.1369_FC4smp #1 SMP Thu Jun 2 
23:08:39 EDT 2005 i686 i686 i386 GNU/Linux
Machine Type: i386-redhat-linux-gnu

Bash Version: 3.0
Patch Level: 16
Release Status: release

Description:
        The expansion of the filename pattern "*.[a-z]* matches files with
        upper case after the period, not just lower case, even though the 
        "nocaseglob" is set to off, when the LANG variable is set to
        "en_US.UTF-8".

Repeat-By:
        date >test.abc
        date >test.ABC
        ls *.[a-z]*
        echo *.[a-z]*

Fix:
        LANG=; export LANG