WHERE: on 3 of my computers, clean installation, various GPUs. WHAT: login screen doesn't allow to type normally and show virtual keyboard, that is about 1/2 of the screen. Rest of screen is black. When I click to hide the keyboard, it hides, but after I want to type password it appears again. It is terribly confusing. I still can type with keyboard and login, but I am unable to choose anything at login screen as virtualkeyboard appears. The bug is described there: https://forum.kde.org/viewtopic.php?f=252&t=143311
It looks like qt5/sddm problem, not related to ksmserver.
This also affected me as well.
Please report issues for the SDDM login manager directly to SDDM developer via https://github.com/sddm/sddm/issues