Seems like mate-power-manager does not work very well in Mabox.
So, it will be replaced with xfce4-power-manager in future releases.
If you like to switch to xfce4-power-manager now…
1. Remove mate-power-manager
yay -R mate-power-manager
# Also remove it from autostart:
rm ~/.config/autostart/mate-power-manager.desktop
2. Install xfce4-power-manager
yay -S xfce4-power-manager
And to be able to disable/enable it with Mabox GUI autostart editor:
cp /etc/xdg/autostart/xfce4-power-manager.desktop ~/.config/autostart/
Also please replace it in Settings Menu super + s
sd mate-power-preferences xfce4-power-manager-settings ~/.config/mabox/settings.csv