Pattern replacement fails if string contains multibyte characters

[Bernd Eggink]

This happens on a utf-8 based system (CRUX 2.3), LANG=de_DE.UTF-8:

t="123abc456äöüABCD"
echo ${t//[a-c]/}
# output: 123456öüCD
# (should be: "123456äöüABCD")

echo ${t//[!a-c]/}
# output: abcäAB
# (should be: "abc")

bash --version:
GNU bash, version 3.2.25(1)-release (i686-pc-linux-gnu)

Without multibyte chars, replacement works as expected. I looks like a 
bug, or am I misssing something?

Regards,
Bernd

--
Bernd Eggink
monoped@sudrala.de
http://sudrala.de