Locale question

$ cat /etc/default/locale
LANG="en_US.UTF-8"
LC_ALL="ru_RU.UTF-8"

$ locale
LANG=en_US.UTF-8
LANGUAGE=
LC_CTYPE="ru_RU.UTF-8"
LC_NUMERIC="ru_RU.UTF-8"
LC_TIME="ru_RU.UTF-8"
LC_COLLATE="ru_RU.UTF-8"
LC_MONETARY="ru_RU.UTF-8"
LC_MESSAGES="ru_RU.UTF-8"
LC_PAPER="ru_RU.UTF-8"
LC_NAME="ru_RU.UTF-8"
LC_ADDRESS="ru_RU.UTF-8"
LC_TELEPHONE="ru_RU.UTF-8"
LC_MEASUREMENT="ru_RU.UTF-8"
LC_IDENTIFICATION="ru_RU.UTF-8"
LC_ALL=ru_RU.UTF-8

2016-02-10 18:33:01.690519|WARNING |ServerLibPriv | |The system locale is set to "C" this can cause unexpected behavior. We advice you to repair your locale!

WAT?

Locale question