SUMMARY

I tried to log in to Plasma on X with an incorrect password as one user from sddm, followed by logging in to Plasma on Wayland with the correct password as another user in a Fedora 35 KDE Plasma installation with Plasma 5.23.5, KF 5.90.0, Qt 5.15.2. The screen went black, and the Plasma splash screen didn't appear. Plasma didn't start normally. sddm reappeared. The failed Plasma startup happened 3/3 times I tried the above steps. 

STEPS TO REPRODUCE
1. Boot a Fedora 35 KDE Plasma installation updated to 2022-2-3 with the updates-testing repo enabled. The system has two normal users shown in sddm.
2.  Try to log in to Plasma on X as the second user with an incorrect password from sddm
3.  Log in to Plasma on Wayland as the first user with the correct password

OBSERVED RESULT
Plasma on Wayland didn't start normally after a failed login attempt as another user to Plasma on X

EXPECTED RESULT
Plasma on Wayland would start normally after a failed login attempt as another user to Plasma on X

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora 35
(available in About System)
KDE Plasma Version: 5.23.5
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2 + patches from KDE/Qt repos

ADDITIONAL INFORMATION
coredumpctl and journalctl didn't have kwin_wayland crashes as happened in my previous report with similar steps at https://bugs.kde.org/show_bug.cgi?id=422711