As recommended in https://bugs.kde.org/show_bug.cgi?id=423477#c12 , opening a new bug: From the KDE menu, I chose 'Switch user'. The lock screen comes up with a button 'Start new session', but without any users displayed. When I hit the button it brings me back to the unlock screen of my original session session Operating System: openSUSE Tumbleweed 20201021 KDE Plasma Version: 5.20.0 KDE Frameworks Version: 5.75.0 Qt Version: 5.15.1
This sounds like an SDDM bug. Are you able to reproduce it today with Plasma 5.27.5 and SDDM from git master (unfortunately it hasn't had a release in over 2 years)?