When I use the Formats module in System Settings to set the local Time format to en_SE this results in ~/.config/plasma-locale-settings.sh trying to set LC_TIME to en_SE.UTF-8 which is not a locale recognized by seemingly anything else. This leads to many programs spewing locale-related errors, including man and perl.

STEPS TO REPRODUCE
1. System Settings > Regional > Detailed Settings > Time > "Sweden - English (en_SE)
2. Apply
3. Log out
4. Log in
5. Open a terminal
6. `perl`
7. `man`

OBSERVED RESULT
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = "en_US",
        LC_ALL = (unset),
        LC_MONETARY = "en_US.UTF-8",
        LC_TIME = "en_SE.UTF-8",
        LC_NUMERIC = "en_US.UTF-8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to a fallback locale ("en_US.UTF-8").

man: can't set the locale; make sure $LC_* and $LANG are correct

EXPECTED RESULT
no errors

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
KDE Plasma Version: 5.14.90
KDE Frameworks Version: 5.54.0
Qt Version: 5.11.3