SUMMARY
When logging in using the wayland session I see the following crashes with such a stacktrace:
       Message: Process 26257 (kded5) of user 1000 dumped core.
                
                Stack trace of thread 26257:
                #0  0x00007f79f1546118 _ZN15QtWaylandClient15QWaylandDisplay13flushRequestsEv (libQt5WaylandClient.so.5 + 0x7c118)
                #1  0x00007f79f1546fd5 _ZN15QtWaylandClient15QWaylandDisplay14forceRoundTripEv (libQt5WaylandClient.so.5 + 0x7cfd5)
                #2  0x00007f79f1547f27 _ZN15QtWaylandClient15QWaylandDisplay15registry_globalEjRK7QStringj (libQt5WaylandClient.so.5 + 0x7df27)
                #3  0x00007f79f15771c6 _ZN9QtWayland11wl_registry13handle_globalEPvP11wl_registryjPKcj (libQt5WaylandClient.so.5 + 0xad1c6)
                #4  0x00007f79f62d7ff5 n/a (libffi.so.7 + 0x6ff5)
                #5  0x00007f79f62d740a n/a (libffi.so.7 + 0x640a)
                #6  0x00007f79f62e63a8 n/a (libwayland-client.so.0 + 0x93a8)
                #7  0x00007f79f62e2c48 n/a (libwayland-client.so.0 + 0x5c48)
                #8  0x00007f79f62e421c wl_display_dispatch_queue_pending (libwayland-client.so.0 + 0x721c)
                #9  0x00007f79f62e467f wl_display_roundtrip_queue (libwayland-client.so.0 + 0x767f)
                #10 0x00007f79f0fcd6b4 _ZN8KWayland6Client16ConnectionThread9roundtripEv (libKF5WaylandClient.so.5 + 0x6c6b4)
                #11 0x00007f79f13d7a2a n/a (KDEPlasmaPlatformTheme.so + 0x41a2a)
                #12 0x00007f79f13bc7a1 n/a (KDEPlasmaPlatformTheme.so + 0x267a1)
                #13 0x00007f79f13da1ab n/a (KDEPlasmaPlatformTheme.so + 0x441ab)
                #14 0x00007f79f558fef8 _ZN21QPlatformThemeFactory6createERK7QStringS2_ (libQt5Gui.so.5 + 0x12cef8)
                #15 0x00007f79f5599c78 _ZN22QGuiApplicationPrivate25createPlatformIntegrationEv (libQt5Gui.so.5 + 0x136c78)
                #16 0x00007f79f559aee8 _ZN22QGuiApplicationPrivate21createEventDispatcherEv (libQt5Gui.so.5 + 0x137ee8)
                #17 0x00007f79f4feac66 _ZN23QCoreApplicationPrivate4initEv (libQt5Core.so.5 + 0x2bbc66)
                #18 0x00007f79f559e003 _ZN22QGuiApplicationPrivate4initEv (libQt5Gui.so.5 + 0x13b003)
                #19 0x00007f79f5d9111d _ZN19QApplicationPrivate4initEv (libQt5Widgets.so.5 + 0x17411d)
                #20 0x000055d64df97edc n/a (kded5 + 0x7edc)
                #21 0x00007f79f49820b3 __libc_start_main (libc.so.6 + 0x270b3)
                #22 0x000055d64df97f4e n/a (kded5 + 0x7f4e)

This stacktrace is similar in klauncher and ksplashqml


STEPS TO REPRODUCE
1. log in using plasma wayland session

OBSERVED RESULT
 black screen, mouse is visible, session is not started, coredumps of kded, klauncher, and ksplashqml can be found with coredumpctl
The only way to login is with x11. Started happening after an update 1-2 months ago.

EXPECTED RESULT
Login


SOFTWARE/OS VERSIONS
Operating System: KDE neon 5.24
KDE Plasma Version: 5.24.0
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.3
Kernel Version: 5.13.0-28-generic (64-bit)
Graphics Platform: X11
Processors: 4 × Intel® Core™ i7-5600U CPU @ 2.60GHz
Memory: 15.5 GiB of RAM
Graphics Processor: llvmpipe


ADDITIONAL INFORMATION
lenovo thinkpad x250 with Intel Corporation HD Graphics 5500