SUMMARY
cannot reproduce on X11

STEPS TO REPRODUCE
1. start Wayland session
2. open system settings > global theme
3. click on "Get new global themes..." button, search for the global theme called "Qogir look-and-feel theme" and install it
4. apply Qogir-light global theme

OBSERVED RESULT
system settings crashes and it can not be started again. "systemsettings5" in Konsole informs segfault.

EXPECTED RESULT
no crash

SOFTWARE/OS VERSIONS
Operating System: KDE neon Unstable Edition
KDE Plasma Version: 5.18.80
KDE Frameworks Version: 5.69.0
Qt Version: 5.14.1


Thread 6 (Thread 0x7fffb5ae2700 (LWP 10128)):
#0  0x00007ffff33edbf9 in __GI___poll (fds=0x7fffb0002de0, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fffeca625c9 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fffeca626dc in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007ffff3d540bc in QEventDispatcherGlib::processEvents (this=0x7fffb0000b20, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#4  0x00007ffff3cf363a in QEventLoop::exec (this=this@entry=0x7fffb5ae1d80, flags=..., flags@entry=...)
    at kernel/qeventloop.cpp:225
#5  0x00007ffff3b04317 in QThread::exec (this=this@entry=0x5555572448d0) at thread/qthread.cpp:536
#6  0x00007ffff1647605 in QQmlThreadPrivate::run (this=0x5555572448d0) at qml/ftw/qqmlthread.cpp:155
#7  0x00007ffff3b057ec in QThreadPrivate::start (arg=0x5555572448d0) at thread/qthread_unix.cpp:342
#8  0x00007fffeee226db in start_thread (arg=0x7fffb5ae2700) at pthread_create.c:463
#9  0x00007ffff33fa88f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7fffcbfff700 (LWP 10126)):
#0  0x00007ffff33edbf9 in __GI___poll (fds=0x7fffc40029e0, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fffeca625c9 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fffeca626dc in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007ffff3d540bc in QEventDispatcherGlib::processEvents (this=0x7fffc4000b20, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#4  0x00007ffff3cf363a in QEventLoop::exec (this=this@entry=0x7fffcbffed80, flags=..., flags@entry=...)
    at kernel/qeventloop.cpp:225
#5  0x00007ffff3b04317 in QThread::exec (this=this@entry=0x555555d92410) at thread/qthread.cpp:536
#6  0x00007ffff1647605 in QQmlThreadPrivate::run (this=0x555555d92410) at qml/ftw/qqmlthread.cpp:155
#7  0x00007ffff3b057ec in QThreadPrivate::start (arg=0x555555d92410) at thread/qthread_unix.cpp:342
#8  0x00007fffeee226db in start_thread (arg=0x7fffcbfff700) at pthread_create.c:463
#9  0x00007ffff33fa88f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7fffd8fa0700 (LWP 10125)):
#0  0x00007ffff33edbf9 in __GI___poll (fds=0x7fffcc002de0, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fffeca625c9 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fffeca626dc in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007ffff3d540bc in QEventDispatcherGlib::processEvents (this=0x7fffcc000b20, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#4  0x00007ffff3cf363a in QEventLoop::exec (this=this@entry=0x7fffd8f9fd80, flags=..., flags@entry=...)
    at kernel/qeventloop.cpp:225
#5  0x00007ffff3b04317 in QThread::exec (this=this@entry=0x555555b320e0) at thread/qthread.cpp:536
#6  0x00007ffff1647605 in QQmlThreadPrivate::run (this=0x555555b320e0) at qml/ftw/qqmlthread.cpp:155
#7  0x00007ffff3b057ec in QThreadPrivate::start (arg=0x555555b320e0) at thread/qthread_unix.cpp:342
#8  0x00007fffeee226db in start_thread (arg=0x7fffd8fa0700) at pthread_create.c:463
#9  0x00007ffff33fa88f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7fffda5d7700 (LWP 10124)):
#0  0x00007fffeee289f3 in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x555555a6b5d8)
    at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  __pthread_cond_wait_common (abstime=0x0, mutex=0x555555a6b588, cond=0x555555a6b5b0) at pthread_cond_wait.c:502
#2  __pthread_cond_wait (cond=0x555555a6b5b0, mutex=0x555555a6b588) at pthread_cond_wait.c:655
#3  0x00007fffdb63decb in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007fffdb63dac7 in ?? () from /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007fffeee226db in start_thread (arg=0x7fffda5d7700) at pthread_create.c:463
#6  0x00007ffff33fa88f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7fffe37d3700 (LWP 10123)):
#0  0x00007ffff33edbf9 in __GI___poll (fds=0x7fffdc002de0, nfds=2, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fffeca625c9 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fffeca626dc in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007ffff3d540bc in QEventDispatcherGlib::processEvents (this=0x7fffdc000b20, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#4  0x00007ffff3cf363a in QEventLoop::exec (this=this@entry=0x7fffe37d2d70, flags=..., flags@entry=...)
    at kernel/qeventloop.cpp:225
#5  0x00007ffff3b04317 in QThread::exec (
    this=this@entry=0x7ffff4458da0 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>)
    at thread/qthread.cpp:536
#6  0x00007ffff41e0555 in QDBusConnectionManager::run (
    this=0x7ffff4458da0 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:179
#7  0x00007ffff3b057ec in QThreadPrivate::start (
    arg=0x7ffff4458da0 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:342
#8  0x00007fffeee226db in start_thread (arg=0x7fffe37d3700) at pthread_create.c:463
#9  0x00007ffff33fa88f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7ffff7fa1800 (LWP 10075)):
#0  0x00007fffef26bd0e in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#1  0x00007fffef26c0aa in XInternAtom () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#2  0x00007fffaf63955b in Kvantum::BlurHelper::BlurHelper(QObject*, QList<double>, QList<double>, double, double, double)
    () from /usr/lib/x86_64-linux-gnu/qt5/plugins/styles/libkvantum.so
#3  0x00007fffaf627008 in Kvantum::Style::polish(QWidget*) ()
   from /usr/lib/x86_64-linux-gnu/qt5/plugins/styles/libkvantum.so
#4  0x00007ffff4e72a0d in QApplication::setStyle (style=<optimized out>) at kernel/qapplication.cpp:1155
#5  0x00007ffff4e73416 in QApplication::setStyle (style=...) at kernel/qapplication.cpp:1211
#6  0x00007fffe6a82f04 in KHintsSettings::slotNotifyChange (this=0x5555557ba5a0, type=<optimized out>, 
    arg=<optimized out>) at ./src/platformtheme/khintssettings.cpp:337
#7  0x00007fffe6a94131 in KHintsSettings::qt_static_metacall (_o=_o@entry=0x5555557ba5a0, _id=_id@entry=3, 
    _a=_a@entry=0x7fffffffc390, _c=QMetaObject::InvokeMetaMethod)
    at ./obj-x86_64-linux-gnu/src/platformtheme/KDEPlasmaPlatformTheme_autogen/EWIEGA46WW/moc_khintssettings.cpp:97
#8  0x00007fffe6a94993 in KHintsSettings::qt_static_metacall (_a=0x7fffffffc390, _id=3, 
    _c=QMetaObject::InvokeMetaMethod, _o=0x5555557ba5a0)
    at ./obj-x86_64-linux-gnu/src/platformtheme/KDEPlasmaPlatformTheme_autogen/EWIEGA46WW/moc_khintssettings.cpp:144
#9  KHintsSettings::qt_metacall (this=0x5555557ba5a0, _c=QMetaObject::InvokeMetaMethod, _id=3, _a=0x7fffffffc390)
    at ./obj-x86_64-linux-gnu/src/platformtheme/KDEPlasmaPlatformTheme_autogen/EWIEGA46WW/moc_khintssettings.cpp:145
#10 0x00007ffff41eb5b8 in QDBusConnectionPrivate::deliverCall (this=<optimized out>, object=<optimized out>, msg=..., 
    metaTypes=..., slotIdx=<optimized out>) at qdbusintegrator.cpp:1001
#11 0x00007ffff3d27e8b in QObject::event (this=0x5555557ba5a0, e=0x7fffdc00c4a0) at kernel/qobject.cpp:1339
#12 0x00007ffff4e6e8bc in QApplicationPrivate::notify_helper (this=this@entry=0x55555579a490, 
    receiver=receiver@entry=0x5555557ba5a0, e=e@entry=0x7fffdc00c4a0) at kernel/qapplication.cpp:3684
#13 0x00007ffff4e75ac0 in QApplication::notify (this=0x7fffffffdd20, receiver=0x5555557ba5a0, e=0x7fffdc00c4a0)
    at kernel/qapplication.cpp:3430
#14 0x00007ffff3cf4db8 in QCoreApplication::notifyInternal2 (receiver=0x5555557ba5a0, event=0x7fffdc00c4a0)
    at kernel/qcoreapplication.cpp:1092
#15 0x00007ffff3cf4f8e in QCoreApplication::sendEvent (receiver=receiver@entry=0x5555557ba5a0, 
    event=event@entry=0x7fffdc00c4a0) at kernel/qcoreapplication.cpp:1487
#16 0x00007ffff3cf7a31 in QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, 
    event_type=event_type@entry=0, data=0x555555790f60) at kernel/qcoreapplication.cpp:1832
#17 0x00007ffff3cf7fc8 in QCoreApplication::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0)
    at kernel/qcoreapplication.cpp:1691
#18 0x00007ffff3d54a13 in postEventSourceDispatch (s=0x5555557bc700) at kernel/qeventdispatcher_glib.cpp:277
#19 0x00007fffeca62417 in g_main_context_dispatch () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#20 0x00007fffeca62650 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#21 0x00007fffeca626dc in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#22 0x00007ffff3d540bc in QEventDispatcherGlib::processEvents (this=0x5555557d3e40, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#23 0x00007fffb70d5610 in runRdb (flags=flags@entry=31) at ./kcms/krdb/krdb.cpp:849
#24 0x00007fffb70c64da in KCMLookandFeel::save (this=<optimized out>) at ./kcms/lookandfeel/kcm.cpp:402
#25 0x00007ffff798a902 in KCModuleQml::save (this=0x555557b5b9c0) at ./src/kcmoduleqml.cpp:322
#26 0x00007ffff79915d7 in KCModuleProxy::save (this=<optimized out>) at ./src/kcmoduleproxy.cpp:239
#27 0x00007ffff7bcbbc1 in ModuleView::moduleSave (this=<optimized out>, module=<optimized out>)
    at ./core/ModuleView.cpp:298
#28 0x00007ffff7bcbeda in ModuleView::moduleSave (this=<optimized out>) at ./core/ModuleView.cpp:289
#29 0x00007ffff7bcf191 in ModuleView::qt_static_metacall (_o=<optimized out>, _id=<optimized out>, _a=0x7fffffffce90, 
    _c=<optimized out>) at ./obj-x86_64-linux-gnu/core/systemsettingsview_autogen/EWIEGA46WW/moc_ModuleView.cpp:122
#30 0x00007ffff3d2fdc9 in doActivate<false> (sender=0x555555b26880, signal_index=9, argv=0x7fffffffce90)
    at kernel/qobject.cpp:3882
#31 0x00007ffff3d2a8a2 in QMetaObject::activate (sender=sender@entry=0x555555b26880, 
    m=m@entry=0x7ffff55546e0 <QAbstractButton::staticMetaObject>, local_signal_index=local_signal_index@entry=2, 
    argv=argv@entry=0x7fffffffce90) at kernel/qobject.cpp:3930
#32 0x00007ffff4f5a552 in QAbstractButton::clicked (this=this@entry=0x555555b26880, _t1=<optimized out>)
    at .moc/moc_qabstractbutton.cpp:313
#33 0x00007ffff4f5a76a in QAbstractButtonPrivate::emitClicked (this=0x555555b268c0) at widgets/qabstractbutton.cpp:415
#34 0x00007ffff4f5bb4a in QAbstractButtonPrivate::click (this=0x555555b268c0) at widgets/qabstractbutton.cpp:408
#35 0x00007ffff4f5bd3d in QAbstractButton::mouseReleaseEvent (this=0x555555b26880, e=0x7fffffffd3f0)
    at widgets/qabstractbutton.cpp:1012
#36 0x00007ffff4eaf7f8 in QWidget::event (this=0x555555b26880, event=0x7fffffffd3f0) at kernel/qwidget.cpp:9031
#37 0x00007ffff4e6e8bc in QApplicationPrivate::notify_helper (this=this@entry=0x55555579a490, 
    receiver=receiver@entry=0x555555b26880, e=e@entry=0x7fffffffd3f0) at kernel/qapplication.cpp:3684
#38 0x00007ffff4e76908 in QApplication::notify (this=<optimized out>, receiver=0x555555b26880, e=0x7fffffffd3f0)
    at kernel/qapplication.cpp:3128
#39 0x00007ffff3cf4db8 in QCoreApplication::notifyInternal2 (receiver=0x555555b26880, event=0x7fffffffd3f0)
    at kernel/qcoreapplication.cpp:1092
#40 0x00007ffff3cf4f9e in QCoreApplication::sendSpontaneousEvent (receiver=receiver@entry=0x555555b26880, 
    event=event@entry=0x7fffffffd3f0) at kernel/qcoreapplication.cpp:1499
#41 0x00007ffff4e74f8f in QApplicationPrivate::sendMouseEvent (receiver=receiver@entry=0x555555b26880, 
    event=event@entry=0x7fffffffd3f0, alienWidget=0x555555b26880, nativeWidget=0x5555557c2f60, 
    buttonDown=buttonDown@entry=0x7ffff557e980 <qt_button_down>, lastMouseReceiver=..., spontaneous=true, 
    onlyDispatchEnterLeave=false) at kernel/qapplication.cpp:2614
#42 0x00007ffff4ec9eb1 in QWidgetWindow::handleMouseEvent (this=this@entry=0x5555558ca850, 
    event=event@entry=0x7fffffffd870) at kernel/qwidgetwindow.cpp:673
#43 0x00007ffff4eccd1a in QWidgetWindow::event (this=0x5555558ca850, event=0x7fffffffd870)
    at kernel/qwidgetwindow.cpp:295
#44 0x00007ffff4e6e8bc in QApplicationPrivate::notify_helper (this=this@entry=0x55555579a490, 
    receiver=receiver@entry=0x5555558ca850, e=e@entry=0x7fffffffd870) at kernel/qapplication.cpp:3684
#45 0x00007ffff4e75ac0 in QApplication::notify (this=0x7fffffffdd20, receiver=0x5555558ca850, e=0x7fffffffd870)
    at kernel/qapplication.cpp:3430
#46 0x00007ffff3cf4db8 in QCoreApplication::notifyInternal2 (receiver=0x5555558ca850, event=0x7fffffffd870)
    at kernel/qcoreapplication.cpp:1092
#47 0x00007ffff3cf4f9e in QCoreApplication::sendSpontaneousEvent (receiver=receiver@entry=0x5555558ca850, 
    event=event@entry=0x7fffffffd870) at kernel/qcoreapplication.cpp:1499
#48 0x00007ffff4580f95 in QGuiApplicationPrivate::processMouseEvent (e=0x55555a89a490) at kernel/qguiapplication.cpp:2209
#49 0x00007ffff45820c5 in QGuiApplicationPrivate::processWindowSystemEvent (e=e@entry=0x55555a89a490)
    at kernel/qguiapplication.cpp:1941
#50 0x00007ffff455b01b in QWindowSystemInterface::sendWindowSystemEvents (flags=...)
    at kernel/qwindowsysteminterface.cpp:1163
#51 0x00007fffe7a2fcd0 in userEventSourceDispatch(_GSource*, int (*)(void*), void*) ()
   from /usr/lib/x86_64-linux-gnu/libQt5WaylandClient.so.5
#52 0x00007fffeca62417 in g_main_context_dispatch () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#53 0x00007fffeca62650 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#54 0x00007fffeca626dc in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#55 0x00007ffff3d540bc in QEventDispatcherGlib::processEvents (this=0x5555557d3e40, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#56 0x00007ffff3cf363a in QEventLoop::exec (this=this@entry=0x7fffffffdc10, flags=..., flags@entry=...)
    at kernel/qeventloop.cpp:225
#57 0x00007ffff3cfcdb0 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1400
#58 0x000055555556077e in main (argc=<optimized out>, argv=<optimized out>) at ./app/main.cpp:101