Gnome works in different locale than /etc/default/locale

Hello I have problem with status bar in Ubuntu 20.04 showing date in German while I have locale set to Czech both in Ubuntu settings and in /etc/default/locale. There is:

LANG=en_US.UTF-8
LC_NUMERIC=cs_CZ.UTF-8
LC_TIME=cs_CZ.UTF-8
LC_MONETARY=cs_CZ.UTF-8
LC_PAPER=cs_CZ.UTF-8
LC_NAME=cs_CZ.UTF-8
LC_ADDRESS=cs_CZ.UTF-8
LC_TELEPHONE=cs_CZ.UTF-8
LC_MEASUREMENT=cs_CZ.UTF-8
LC_IDENTIFICATION=cs_CZ.UTF-8

which is correct. The command locale shows:

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

which is incorrect. I have changed LC_TIME from de to cs manually and command date shows date correctly in Czech yet gnome even after restart still shows german date in status line. Why is locale not taken from /etc/default/locale when gnome starts?

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