Manjaro-settings-manager language issue

I have an issue with the manjaro-settings-manager. Trying to install additional language-packs as well as removing/adding languages does not have any effect. Using the locale-gen script didn’t change anything, reboot, uncommenting the language in /etc/locale.gen same thing, no change.
I’m not asked for the root-password. Output in the manjaro-settings-manager -d mode is “failed to set locale”
This is my first post here, so please ask me for further information, if required.
Btw. it is a complete new install, preconfigured by Tuxedo…

see this

Thank you so far. I did this workaround already, but still the MSM seems not to have any “admin permissions” to set changes or install additional language packs. I have to set the language in firefox, thunderbird, libreoffice etc. to german after every update…
/etc/locale.gen shows the locales set corectly, as well as the output of locale or locale -a.

I’m having the same issue with a freshly installed system by Tuxedo!
Manjaro Settings Manager doesn’t ask for password and just fails without any meaningful errors.
journalctl confirms this is a permissions issue:

[system] Activating service name='org.manjaro.msm.languagepackages' requested by ':1.48' (uid=30000 pid=1495 comm="/usr/bin/systemsettings ") (using servicehelper)
[system] Activated service 'org.manjaro.msm.languagepackages' failed: Failed to execute program org.manjaro.msm.languagepackages: Permission denied

I did not apply the workaround.

Edit: I’m on KDE, not XFCE, so I guess both variants are affected.