SUMMARY
Within a minute of login, both screens go black. No user action is required nor does user action avoid crash after login. Sometimes the KDE crash handler appears. If I switch to another tty (CNTL+ALT+F2) before returning to the SDDM lock screen on tty1, the crash can be avoided.

SOFTWARE/OS VERSIONS
Operating System: Kubuntu 24.04
KDE Plasma Version: 5.27.11
KDE Frameworks Version: 5.115.0
Qt Version: 5.15.13
Kernel Version: 6.8.0-49-generic (64-bit)
Graphics Platform: X11
Processors: 12 × AMD Ryzen 5 5600X 6-Core Processor
Memory: 15.5 GiB of RAM
Graphics Processor: NVIDIA GeForce RTX 3060 Ti/PCIe/SSE2
Manufacturer: ASUS

BACKTRACE
```
[Thread 0x7814cb2006c0 (LWP 2456) exited]
[Thread 0x7814dbc006c0 (LWP 2411) exited]

Thread 1 "kwin_x11" received signal SIGSEGV, Segmentation fault.
0x00007814e301864f in KWin::Workspace::workspaceEvent(xcb_generic_event_t*) () from /lib/x86_64-linux-gnu/libkwin.so.5

Thread 6 (Thread 0x7814d12006c0 (LWP 2441) "QDBusConnection"):
#0  0x00007814e031b4cd in __GI___poll (fds=0x7814cc001350, nfds=3, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007814def7366e in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007814def13a53 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007814e1735279 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007814e16d6a7b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007814e14da36b in QThread::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007814e091815b in ?? () from /lib/x86_64-linux-gnu/libQt5DBus.so.5
#7  0x00007814e14db674 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007814e029ca94 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:447
#9  0x00007814e0329c3c in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78

Thread 4 (Thread 0x7814ca8006c0 (LWP 2470) "QQmlThread"):
#0  0x00007814e031b4cd in __GI___poll (fds=0x7814bc001390, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007814def7366e in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007814def13a53 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007814e1735279 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007814e16d6a7b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007814e14da36b in QThread::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007814e254107a in ?? () from /lib/x86_64-linux-gnu/libQt5Qml.so.5
#7  0x00007814e14db674 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007814e029ca94 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:447
#9  0x00007814e0329c3c in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78

Thread 3 (Thread 0x7814c90006c0 (LWP 2526) "vsync event mon"):
#0  0x00007814e031b4cd in __GI___poll (fds=0x7814b00013b0, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007814def7366e in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007814def13a53 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007814e1735279 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007814e16d6a7b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007814e14da36b in QThread::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007814e14db674 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007814e029ca94 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:447
#8  0x00007814e0329c3c in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78

Thread 2 (Thread 0x7814c0e006c0 (LWP 2562) "CPMMListener"):
#0  0x00007814e031b4cd in __GI___poll (fds=0x7814c0dffbe8, nfds=1, timeout=300000) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007814d9013fc7 in ?? () from /lib/x86_64-linux-gnu/libnvidia-glcore.so.550.120
#2  0x00007814d8ff5754 in ?? () from /lib/x86_64-linux-gnu/libnvidia-glcore.so.550.120
#3  0x00007814e029ca94 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:447
#4  0x00007814e0329c3c in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78

Thread 1 (Thread 0x7814dc40ee80 (LWP 2405) "kwin_x11"):
#0  0x00007814e301864f in KWin::Workspace::workspaceEvent(xcb_generic_event_t*) () from /lib/x86_64-linux-gnu/libkwin.so.5
#1  0x00007814e16d54af in QAbstractEventDispatcher::filterNativeEvent(QByteArray const&, void*, long*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007814dbcd3086 in QXcbConnection::handleXcbEvent(xcb_generic_event_t*) () from /lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#3  0x00007814dbcd479f in QXcbConnection::processXcbEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#4  0x00007814dbcfccff in ?? () from /lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#5  0x00007814def145b5 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#6  0x00007814def73717 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#7  0x00007814def13a53 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#8  0x00007814e1735279 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007814e16d6a7b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007814e16df3e8 in QCoreApplication::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#11 0x00005f7491fc0ba1 in ?? ()
#12 0x00007814e022a1ca in __libc_start_call_main (main=main@entry=0x5f7491fc04f0, argc=argc@entry=2, argv=argv@entry=0x7ffcf0677b48) at ../sysdeps/nptl/libc_start_call_main.h:58
#13 0x00007814e022a28b in __libc_start_main_impl (main=0x5f7491fc04f0, argc=2, argv=0x7ffcf0677b48, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffcf0677b38) at ../csu/libc-start.c:360
#14 0x00005f7491fc20e5 in ?? ()
A debugging session is active.

        Inferior 1 [process 2405] will be detached.

Quit anyway? (y or n) [answered Y; input not from terminal]
[Inferior 1 (process 2405) detached]
```