My attempt to use markup formatting appears to have caused the web interface to not display the text, so here is the plain version (minus the first line, which did come through). My apologies if this is redundant.

The demonstration:

$ cat Demo
# shell script
for i in "$@"; do
  case "$i" in
    [A-Z]) echo "$i has upper case";;
  esac
done
$ env - LANG=en_US.UTF-8 ./bash ./Demo a b C y z
b has upper case
C has upper case
y has upper case
z has upper case
$

This was tested with a fresh-compiled build from the latest git tip on 64-bit Ubuntu 14.04. I can (re)produce this behavior in at least Bash 4.3.11 (Ubuntu 14.04), 4.2.47 (Fedora 20), and 4.2.25 (Ubuntu 12.04).

Assuming that it is desirable for '*[A-Z]*' to match lower case characters at all in this context (I believe that it is a mistake to do so and it certainly doesn't match the behavior of other POSIX-compatible shells), bash should at least match 'a' too.

A mirror image of this bug happens if you use '*[a-z]*' and test against upper case letters; 'Z' does not match although A-Y do.