Linux Mint is using light-dm now and the .desktop file looks for the "lightdm-settings" icon. This can be fixed by the user to be "lightdm-gtk-greeter-settings" for which there is a Numix Circle icon, but an additional icon link with the name "lightdm-settings" pointing to "login.svg" would be a permanent fix. Issues also affects numix-icon-theme-square.
Not the most important issue by any means, but easy to fix.
Linux Mint is using light-dm now and the .desktop file looks for the "lightdm-settings" icon. This can be fixed by the user to be "lightdm-gtk-greeter-settings" for which there is a Numix Circle icon, but an additional icon link with the name "lightdm-settings" pointing to "login.svg" would be a permanent fix. Issues also affects numix-icon-theme-square.
Not the most important issue by any means, but easy to fix.