I have FreeBSD 12.1 installed in a VM. I have installed the latest KDE and SDDM via "pkg install kde5" and "pkg install sddm". As this is on a VM for testing, I have not set a password for my user account to log into KDE (root does have a password through).
I can log in successfully by entering a blank password, and use KDE without any problems, but if I let the system timeout such that it takes me back to the SDDM login screen, the empty password is not recognised and won't let me in again. I get an "Unlocking failed" error message.
FreeBSD 12.1. KDE 5.17