Fedora :: File Name Globbing No Longer Case Sensitive In Core 12?

Some of my files and directories were mysteriously disappearing and some of my shell scripts were failing after the upgrade to Fedora Core 12. After some debugging I found out that file name globbing is no longer case sensitive in Fedora Core 12, that is

rm -rf [a-z]*

now also trashes all files and directories starting with [A-Z], which explains the removed files and directories

and

ls [a-z]*

now also includes files and directories starting with [A-Z], which caused my shell scripts to fail.

Is this a bug or a 'feature'?