I can confirm this bug using the ISO-8859-1 version of the en_DK locale. It might be specific to en_DK.
nkbj@hafnium:~$ locale LANG=en_DK LANGUAGE=en_DK:en LC_CTYPE="en_DK" LC_NUMERIC="en_DK" LC_TIME="en_DK" LC_COLLATE="en_DK" LC_MONETARY="en_DK" LC_MESSAGES="en_DK" LC_PAPER="en_DK" LC_NAME="en_DK" LC_ADDRESS="en_DK" LC_TELEPHONE="en_DK" LC_MEASUREMENT="en_DK" LC_IDENTIFICATION="en_DK" LC_ALL=
I can confirm this bug using the ISO-8859-1 version of the en_DK locale. It might be specific to en_DK.
nkbj@hafnium:~$ locale "en_DK" "en_DK" ON="en_ DK"
LANG=en_DK
LANGUAGE=en_DK:en
LC_CTYPE="en_DK"
LC_NUMERIC="en_DK"
LC_TIME="en_DK"
LC_COLLATE="en_DK"
LC_MONETARY="en_DK"
LC_MESSAGES="en_DK"
LC_PAPER="en_DK"
LC_NAME="en_DK"
LC_ADDRESS="en_DK"
LC_TELEPHONE=
LC_MEASUREMENT=
LC_IDENTIFICATI
LC_ALL=