SUMMARY
While I was using my system, the windows flashed black for a moment, then I got a crash notification for kwin. I don't remember exactly what I was doing at that time, so I am unable to reproduce it.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 5.26.90
KDE Frameworks Version: 5.102.0
Qt Version: 5.15.8
Kernel Version: 6.1.7-arch1-1 (64-bit)
Graphics Platform: X11
Graphics Processor: AMD Radeon Vega 8 Graphics

BACKTRACE
#0  __GI___pthread_sigmask (how=1, newmask=<optimized out>, oldmask=0x0) at pthread_sigmask.c:43
#1  0x00007f0aa0c51bdd in __GI___sigprocmask (how=<optimized out>, set=<optimized out>, oset=<optimized out>)
    at ../sysdeps/unix/sysv/linux/sigprocmask.c:25
#2  0x00007f0aa3d121eb in KCrash::setCrashHandler(void (*)(int)) (handler=handler@entry=0x0) at /usr/src/debug/kcrash/kcrash-5.102.0/src/kcrash.cpp:414
#3  0x00007f0aa3d147e6 in KCrash::defaultCrashHandler(int) (sig=11) at /usr/src/debug/kcrash/kcrash-5.102.0/src/kcrash.cpp:625
#4  0x00007f0aa0c519e0 in <signal handler called> () at /usr/lib/libc.so.6
#5  0x0000000000000de1 in  ()
#6  0x000055c7cb669460 in  ()
#7  0x000055c7cb66a5b8 in  ()
#8  0x00007f0aa3814cb7 in KWin::EffectsHandlerImpl::highlightWindows(QVector<KWin::EffectWindow*> const&) () at /usr/lib/libkwin.so.5
#9  0x00007f0aa3a8cbe2 in  () at /usr/lib/libkwin.so.5
#10 0x00007f0aa3a9238c in  () at /usr/lib/libkwin.so.5
#11 0x00007f0aa3a8bd47 in KWin::TabBox::TabBox::close(bool) () at /usr/lib/libkwin.so.5
#12 0x00007f0aa3a8c06b in KWin::TabBox::TabBox::accept(bool) () at /usr/lib/libkwin.so.5
#13 0x00007f0aa3a8c2f3 in KWin::TabBox::TabBox::modifiersReleased() () at /usr/lib/libkwin.so.5
#14 0x00007f0aa3a951fd in  () at /usr/lib/libkwin.so.5
#15 0x00007f0aa385d6bf in KWin::Application::dispatchEvent(xcb_generic_event_t*) () at /usr/lib/libkwin.so.5
#16 0x00007f0aa1e8470f in QAbstractEventDispatcher::filterNativeEvent(QByteArray const&, void*, long*)
    (this=<optimized out>, eventType=..., message=message@entry=0x7f0a8c069290, result=result@entry=0x7ffc9d221620)
    at kernel/qabstracteventdispatcher.cpp:495
#17 0x00007f0a9c506f71 in QXcbConnection::handleXcbEvent(xcb_generic_event_t*) (this=this@entry=0x55c7ccd623c0, event=event@entry=0x7f0a8c069290)
    at /usr/src/debug/qt5-base/qtbase/src/plugins/platforms/xcb/qxcbconnection.cpp:579
#18 0x00007f0a9c50b550 in QXcbConnection::processXcbEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x55c7ccd623c0, flags=...)
    at /usr/src/debug/qt5-base/qtbase/src/plugins/platforms/xcb/qxcbconnection.cpp:1065
#19 0x00007f0a9c52f9c8 in xcbSourceDispatch(GSource*, GSourceFunc, gpointer) (source=<optimized out>)
    at /usr/src/debug/qt5-base/qtbase/src/plugins/platforms/xcb/qxcbeventdispatcher.cpp:103
#20 0x00007f0a9fc6d87b in g_main_dispatch (context=0x7f0a94005010) at ../glib/glib/gmain.c:3454
#21 g_main_context_dispatch (context=0x7f0a94005010) at ../glib/glib/gmain.c:4172
#22 0x00007f0a9fcc4c89 in g_main_context_iterate.constprop.0 (context=0x7f0a94005010, block=1, dispatch=1, self=<optimized out>)
    at ../glib/glib/gmain.c:4248
#23 0x00007f0a9fc6c132 in g_main_context_iteration (context=0x7f0a94005010, may_block=1) at ../glib/glib/gmain.c:4313
#24 0x00007f0aa1ed8b2c in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x55c7cce59210, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#25 0x00007f0aa1e865ac in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7ffc9d2219a0, flags=...)
    at ../../include/QtCore/../../src/corelib/global/qflags.h:69
#26 0x00007f0aa1e910d9 in QCoreApplication::exec() () at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#27 0x000055c7cb62ec94 in  ()
#28 0x00007f0aa0c3c290 in __libc_start_call_main (main=main@entry=0x55c7cb62e880, argc=argc@entry=2, argv=argv@entry=0x7ffc9d221c98) at ../sysdeps/nptl/libc_start_call_main.h:58
#29 0x00007f0aa0c3c34a in __libc_start_main_impl (main=0x55c7cb62e880, argc=2, argv=0x7ffc9d221c98, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffc9d221c88) at ../csu/libc-start.c:381
#30 0x000055c7cb630205 in  ()