I want to have 24hr time so used system-settings to select "Defaut C" in the "time".

This results in "LC_TIME=C.UTF-8" when I run dnf I get the following warning message.

Failed to set locale, defaulting to C

If I export LC_TIME=C I don't get the warning.

So, is dnf to blame or is the setting of C.UTF-8 incorrect?