STEPS TO REPRODUCE
1. use Wayland session
2. connect an external monitor to hdmi port
3. press meta+p and choose 'Switch to external screen'
4. press meta+p again and choose 'Unify outputs'

OBSERVED RESULT
Plasma crashes

EXPECTED RESULT
no crash

SOFTWARE/OS VERSIONS
Operating System: KDE neon Unstable Edition
KDE Plasma Version: 5.24.80
KDE Frameworks Version: 5.94.0
Qt Version: 5.15.3
Graphics Platform: Wayland


Thread 11 (Thread 0x7fce9ffff700 (LWP 4628)):
#0  0x00007fcea9bb69cf in __GI___poll (fds=0x7fce90004a60, nfds=3, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fcea844536e in g_main_context_poll (priority=<optimized out>, n_fds=3, fds=0x7fce90004a60, timeout=<optimized out>, context=0x7fce90000c20) at ../../../glib/gmain.c:4346
#2  g_main_context_iterate (context=context@entry=0x7fce90000c20, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:4042
#3  0x00007fcea84454a3 in g_main_context_iteration (context=0x7fce90000c20, may_block=may_block@entry=1) at ../../../glib/gmain.c:4108
#4  0x00007fceaa187642 in QEventDispatcherGlib::processEvents (this=0x7fce90000b60, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#5  0x00007fceaa12b87b in QEventLoop::exec (this=this@entry=0x7fce9fffebb0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#6  0x00007fcea9f45442 in QThread::exec (this=this@entry=0x7fceaac63d80 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#7  0x00007fceaabdff4b in QDBusConnectionManager::run (this=0x7fceaac63d80 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:179
#8  0x00007fcea9f46623 in QThreadPrivate::start (arg=0x7fceaac63d80 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:331
#9  0x00007fcea98da609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x00007fcea9bc3163 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 10 (Thread 0x7fce9d94d700 (LWP 4630)):
#0  0x00007fcea9bb69cf in __GI___poll (fds=0x7fce88004e60, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fcea844536e in g_main_context_poll (priority=<optimized out>, n_fds=1, fds=0x7fce88004e60, timeout=<optimized out>, context=0x7fce88000c20) at ../../../glib/gmain.c:4346
#2  g_main_context_iterate (context=context@entry=0x7fce88000c20, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:4042
#3  0x00007fcea84454a3 in g_main_context_iteration (context=0x7fce88000c20, may_block=may_block@entry=1) at ../../../glib/gmain.c:4108
#4  0x00007fceaa187642 in QEventDispatcherGlib::processEvents (this=0x7fce88000b60, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#5  0x00007fceaa12b87b in QEventLoop::exec (this=this@entry=0x7fce9d94cbe0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#6  0x00007fcea9f45442 in QThread::exec (this=<optimized out>) at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#7  0x00007fcea9f46623 in QThreadPrivate::start (arg=0x55a2a539fe00) at thread/qthread_unix.cpp:331
#8  0x00007fcea98da609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x00007fcea9bc3163 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 9 (Thread 0x7fce9caa8700 (LWP 4631)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55a2a53eeb78) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x55a2a53eeb28, cond=0x55a2a53eeb50) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x55a2a53eeb50, mutex=0x55a2a53eeb28) at pthread_cond_wait.c:638
#3  0x00007fce8f1475eb in cnd_wait (mtx=0x55a2a53eeb28, cond=0x55a2a53eeb50) at ../include/c11/threads_posix.h:155
#4  util_queue_thread_func (input=input@entry=0x55a2a561d670) at ../src/util/u_queue.c:294
#5  0x00007fce8f1471eb in impl_thrd_routine (p=<optimized out>) at ../include/c11/threads_posix.h:87
#6  0x00007fcea98da609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#7  0x00007fcea9bc3163 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 8 (Thread 0x7fce6908b700 (LWP 4669)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55a2a581fb70) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x55a2a581fb20, cond=0x55a2a581fb48) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x55a2a581fb48, mutex=0x55a2a581fb20) at pthread_cond_wait.c:638
#3  0x00007fcea9f4c68b in QWaitConditionPrivate::wait (deadline=..., this=0x55a2a581fb20) at thread/qwaitcondition_unix.cpp:146
#4  QWaitCondition::wait (this=this@entry=0x55a2a6039aa8, mutex=mutex@entry=0x55a2a6039aa0, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007fceabbcd074 in QSGRenderThreadEventQueue::takeEvent (wait=true, this=0x55a2a6039a98) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qdeadlinetimer.h:68
#6  QSGRenderThread::processEventsAndWaitForMore (this=this@entry=0x55a2a6039a00) at scenegraph/qsgthreadedrenderloop.cpp:936
#7  0x00007fceabbcd4e9 in QSGRenderThread::run (this=0x55a2a6039a00) at scenegraph/qsgthreadedrenderloop.cpp:1053
#8  0x00007fcea9f46623 in QThreadPrivate::start (arg=0x55a2a6039a00) at thread/qthread_unix.cpp:331
#9  0x00007fcea98da609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x00007fcea9bc3163 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 7 (Thread 0x7fce9edee700 (LWP 4629)):
#0  0x00007fcea9bb69cf in __GI___poll (fds=0x7fce94004e60, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fcea844536e in g_main_context_poll (priority=<optimized out>, n_fds=1, fds=0x7fce94004e60, timeout=<optimized out>, context=0x7fce94000c20) at ../../../glib/gmain.c:4346
#2  g_main_context_iterate (context=context@entry=0x7fce94000c20, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:4042
#3  0x00007fcea84454a3 in g_main_context_iteration (context=0x7fce94000c20, may_block=may_block@entry=1) at ../../../glib/gmain.c:4108
#4  0x00007fceaa187642 in QEventDispatcherGlib::processEvents (this=0x7fce94000b60, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#5  0x00007fceaa12b87b in QEventLoop::exec (this=this@entry=0x7fce9ededbc0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#6  0x00007fcea9f45442 in QThread::exec (this=this@entry=0x55a2a50a58e0) at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#7  0x00007fceab76bb39 in QQmlThreadPrivate::run (this=0x55a2a50a58e0) at qml/ftw/qqmlthread.cpp:155
#8  0x00007fcea9f46623 in QThreadPrivate::start (arg=0x55a2a50a58e0) at thread/qthread_unix.cpp:331
#9  0x00007fcea98da609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x00007fcea9bc3163 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x7fcea49a8700 (LWP 4627)):
#0  0x00007fcea9bb69cf in __GI___poll (fds=fds@entry=0x7fcea49a7be0, nfds=nfds@entry=2, timeout=timeout@entry=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fcea7f9ca36 in poll (__timeout=-1, __nfds=2, __fds=0x7fcea49a7be0) at /usr/include/x86_64-linux-gnu/bits/poll2.h:46
#2  QtWaylandClient::EventThread::run (this=0x55a2a4f88fe0) at qwaylanddisplay.cpp:208
#3  0x00007fcea9f46623 in QThreadPrivate::start (arg=0x55a2a4f88fe0) at thread/qthread_unix.cpp:331
#4  0x00007fcea98da609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#5  0x00007fcea9bc3163 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7fce6ab6a700 (LWP 4663)):
#0  0x00007fcea9bb69cf in __GI___poll (fds=0x7fce5c006750, nfds=1, timeout=3499307) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fcea844536e in g_main_context_poll (priority=<optimized out>, n_fds=1, fds=0x7fce5c006750, timeout=<optimized out>, context=0x7fce5c000c20) at ../../../glib/gmain.c:4346
#2  g_main_context_iterate (context=context@entry=0x7fce5c000c20, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:4042
#3  0x00007fcea84454a3 in g_main_context_iteration (context=0x7fce5c000c20, may_block=may_block@entry=1) at ../../../glib/gmain.c:4108
#4  0x00007fceaa187642 in QEventDispatcherGlib::processEvents (this=0x7fce5c000b60, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#5  0x00007fceaa12b87b in QEventLoop::exec (this=this@entry=0x7fce6ab69ba0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#6  0x00007fcea9f45442 in QThread::exec (this=this@entry=0x55a2a98dd500) at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#7  0x00007fce69fa00bc in KCupsConnection::run (this=0x55a2a98dd500) at ./libkcups/KCupsConnection.cpp:289
#8  0x00007fcea9f46623 in QThreadPrivate::start (arg=0x55a2a98dd500) at thread/qthread_unix.cpp:331
#9  0x00007fcea98da609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x00007fcea9bc3163 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7fce83fff700 (LWP 4632)):
#0  0x00007fcea9bb69cf in __GI___poll (fds=0x7fce7c004a30, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fcea844536e in g_main_context_poll (priority=<optimized out>, n_fds=1, fds=0x7fce7c004a30, timeout=<optimized out>, context=0x7fce7c000c20) at ../../../glib/gmain.c:4346
#2  g_main_context_iterate (context=context@entry=0x7fce7c000c20, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:4042
#3  0x00007fcea84454a3 in g_main_context_iteration (context=0x7fce7c000c20, may_block=may_block@entry=1) at ../../../glib/gmain.c:4108
#4  0x00007fceaa187642 in QEventDispatcherGlib::processEvents (this=0x7fce7c000b60, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#5  0x00007fceaa12b87b in QEventLoop::exec (this=this@entry=0x7fce83ffeba0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:141
#6  0x00007fcea9f45442 in QThread::exec (this=this@entry=0x55a2a608e5c0) at ../../include/QtCore/../../src/corelib/global/qflags.h:121
#7  0x00007fceabb0743a in QQuickPixmapReader::run (this=0x55a2a608e5c0) at util/qquickpixmapcache.cpp:1024
#8  0x00007fcea9f46623 in QThreadPrivate::start (arg=0x55a2a608e5c0) at thread/qthread_unix.cpp:331
#9  0x00007fcea98da609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x00007fcea9bc3163 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7fce817fa700 (LWP 4640)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55a2a614e630) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x55a2a614e5e0, cond=0x55a2a614e608) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x55a2a614e608, mutex=0x55a2a614e5e0) at pthread_cond_wait.c:638
#3  0x00007fcea9f4c68b in QWaitConditionPrivate::wait (deadline=..., this=0x55a2a614e5e0) at thread/qwaitcondition_unix.cpp:146
#4  QWaitCondition::wait (this=this@entry=0x55a2a614db68, mutex=mutex@entry=0x55a2a614db60, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007fceabbcd074 in QSGRenderThreadEventQueue::takeEvent (wait=true, this=0x55a2a614db58) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qdeadlinetimer.h:68
#6  QSGRenderThread::processEventsAndWaitForMore (this=this@entry=0x55a2a614dac0) at scenegraph/qsgthreadedrenderloop.cpp:936
#7  0x00007fceabbcd4e9 in QSGRenderThread::run (this=0x55a2a614dac0) at scenegraph/qsgthreadedrenderloop.cpp:1053
#8  0x00007fcea9f46623 in QThreadPrivate::start (arg=0x55a2a614dac0) at thread/qthread_unix.cpp:331
#9  0x00007fcea98da609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x00007fcea9bc3163 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7fcea51a9700 (LWP 4626)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x55a2a4f88cb0) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x55a2a4f88c60, cond=0x55a2a4f88c88) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x55a2a4f88c88, mutex=0x55a2a4f88c60) at pthread_cond_wait.c:638
#3  0x00007fcea9f4c68b in QWaitConditionPrivate::wait (deadline=..., this=0x55a2a4f88c60) at thread/qwaitcondition_unix.cpp:146
#4  QWaitCondition::wait (this=this@entry=0x55a2a4f82da0, mutex=mutex@entry=0x55a2a4f82d98, deadline=...) at thread/qwaitcondition_unix.cpp:225
#5  0x00007fcea7f9c9dd in QtWaylandClient::EventThread::waitForReading (this=0x55a2a4f82d60) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qdeadlinetimer.h:68
#6  QtWaylandClient::EventThread::run (this=0x55a2a4f82d60) at qwaylanddisplay.cpp:206
#7  0x00007fcea9f46623 in QThreadPrivate::start (arg=0x55a2a4f82d60) at thread/qthread_unix.cpp:331
#8  0x00007fcea98da609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x00007fcea9bc3163 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7fcea5cf09c0 (LWP 4625)):
#0  __GI_raise (sig=sig@entry=11) at ../sysdeps/unix/sysv/linux/raise.c:50
#1  0x00007fceac046ff5 in KCrash::defaultCrashHandler (sig=11) at ./src/kcrash.cpp:618
#2  <signal handler called>
#3  PlasmaQuick::ContainmentView::containment (this=0x0) at ./src/plasmaquick/containmentview.cpp:256
#4  0x000055a2a3adc6e6 in ShellCorona::screenForContainment (this=0x55a2a4f6d750, containment=<optimized out>) at ./shell/shellcorona.cpp:1947
#5  0x000055a2a3adc65f in ShellCorona::screenForContainment (this=0x55a2a4f6d750, containment=<optimized out>) at ./shell/shellcorona.cpp:1939
#6  0x00007fcea4061d21 in AppletInterface::screenGeometry (this=0x55a2a55a6e90) at ./src/scriptengines/qml/plasmoid/appletinterface.cpp:622
#7  0x00007fcea40658f8 in AppletInterface::qt_static_metacall (_o=_o@entry=0x55a2a55a6e90, _c=_c@entry=QMetaObject::ReadProperty, _id=_id@entry=25, _a=_a@entry=0x7fff2c491890) at ./obj-x86_64-linux-gnu/src/scriptengines/qml/plasma_appletscript_declarative_autogen/include/moc_appletinterface.cpp:771
#8  0x00007fcea406717b in AppletInterface::qt_metacall (this=0x55a2a55a6e90, _c=QMetaObject::ReadProperty, _id=25, _a=0x7fff2c491890) at ./obj-x86_64-linux-gnu/src/scriptengines/qml/plasma_appletscript_declarative_autogen/include/moc_appletinterface.cpp:872
#9  0x00007fceab730cd0 in QV4::QQmlValueTypeReference::readReferenceValue (this=0x7fce9e1af510) at /usr/include/c++/9/bits/atomic_base.h:413
#10 QV4::QQmlValueTypeReference::readReferenceValue (this=0x7fce9e1af510) at qml/qqmlvaluetypewrapper.cpp:125
#11 0x00007fceab731b09 in QV4::QQmlValueTypeWrapper::virtualResolveLookupGetter (object=0x7fce9e1af510, engine=0x55a2a508bbe0, lookup=0x55a2a9957060) at qml/qqmlvaluetypewrapper.cpp:446
#12 0x00007fceab731025 in QV4::QQmlValueTypeWrapper::<lambda()>::operator() (__closure=<synthetic pointer>) at qml/qqmlvaluetypewrapper.cpp:468
#13 QV4::QQmlValueTypeWrapper::lookupGetter (lookup=0x55a2a9957060, engine=0x55a2a508bbe0, object=...) at qml/qqmlvaluetypewrapper.cpp:480
#14 0x00007fce6909624c in ?? ()
#15 0x0000000000000000 in ?? ()