On openSuse Leap 15.0 with
KDE Frameworks 5.59.0
Qt 5.13.0 (built against 5.13.0)

immediately when starting akonadi (e.g. on login or manually "aconadictl start")
the /usr/bin/akonadi_davgroupware_resource crashes with the following backtrace.
The server for the dav_groupware is a nextcloud server, syncing calendar and contacts. It worked until recently with KDE 17.04

Application: akonadi_davgroupware_resource (akonadi_davgroupware_resource), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f53fbb7e900 (LWP 28235))]

Thread 5 (Thread 0x7f53d5d26700 (LWP 28241)):
#0  0x00007f53f670b7da in recv () from /lib64/libc.so.6
#1  0x00007f53f3f9ddec in ?? () from /usr/lib64/libQt5Network.so.5
#2  0x00007f53f3f8e4a5 in ?? () from /usr/lib64/libQt5Network.so.5
#3  0x00007f53f3f8ecf4 in QNetworkInterface::allInterfaces() () from /usr/lib64/libQt5Network.so.5
#4  0x00007f53d50d1b96 in ?? () from /usr/lib64/qt5/plugins/bearer/libqgenericbearer.so
#5  0x00007f53f7219bc5 in QMetaMethod::invoke (this=this@entry=0x7f53d5d25320, object=object@entry=0x56499297b810, connectionType=Qt::DirectConnection, connectionType@entry=Qt::AutoConnection, returnValue=..., val0=..., val1=..., val2=..., val3=..., val4=..., val5=..., val6=..., val7=..., val8=..., val9=...) at kernel/qmetaobject.cpp:2301
#6  0x00007f53f721bb18 in QMetaObject::invokeMethod (obj=0x56499297b810, member=0x7f53f4013dc4 "requestUpdate", type=Qt::AutoConnection, ret=..., val0=..., val1=..., val2=..., val3=..., val4=..., val5=..., val6=..., val7=..., val8=..., val9=...) at kernel/qmetaobject.cpp:1515
#7  0x00007f53f3f7bd0b in QNetworkConfigurationManagerPrivate::pollEngines() () from /usr/lib64/libQt5Network.so.5
#8  0x00007f53f40082c5 in ?? () from /usr/lib64/libQt5Network.so.5
#9  0x00007f53f72392e5 in QMetaObject::activate (sender=sender@entry=0x7f53cc050420, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=0, argv=<optimized out>, argv@entry=0x7f53d5d258f0) at kernel/qobject.cpp:3807
#10 0x00007f53f72399a7 in QMetaObject::activate (sender=sender@entry=0x7f53cc050420, m=m@entry=0x7f53f76beb60 <QTimer::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7f53d5d258f0) at kernel/qobject.cpp:3658
#11 0x00007f53f7245fa7 in QTimer::timeout (this=this@entry=0x7f53cc050420, _t1=...) at .moc/moc_qtimer.cpp:205
#12 0x00007f53f7246308 in QTimer::timerEvent (this=0x7f53cc050420, e=<optimized out>) at kernel/qtimer.cpp:255
#13 0x00007f53f7239dfb in QObject::event (this=0x7f53cc050420, e=<optimized out>) at kernel/qobject.cpp:1282
#14 0x00007f53f7208971 in doNotify (event=0x7f53d5d25a60, receiver=0x7f53cc050420) at kernel/qcoreapplication.cpp:1155
#15 QCoreApplication::notify (event=<optimized out>, receiver=<optimized out>, this=<optimized out>) at kernel/qcoreapplication.cpp:1141
#16 QCoreApplication::notifyInternal2 (receiver=0x7f53cc050420, event=0x7f53d5d25a60) at kernel/qcoreapplication.cpp:1065
#17 0x00007f53f7265989 in QTimerInfoList::activateTimers (this=0x7f53cc004ce0) at kernel/qtimerinfo_unix.cpp:643
#18 0x00007f53f7266151 in timerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:183
#19 0x00007f53efb1ef07 in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
#20 0x00007f53efb1f2b0 in ?? () from /usr/lib64/libglib-2.0.so.0
#21 0x00007f53efb1f33c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#22 0x00007f53f726651b in QEventDispatcherGlib::processEvents (this=0x7f53cc000b10, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#23 0x00007f53f7206baa in QEventLoop::exec (this=this@entry=0x7f53d5d25cb0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#24 0x00007f53f7022dba in QThread::exec (this=<optimized out>) at thread/qthread.cpp:531
#25 0x00007f53f7024562 in QThreadPrivate::start (arg=0x564992a07870) at thread/qthread_unix.cpp:360
#26 0x00007f53f2813569 in start_thread () from /lib64/libpthread.so.0
#27 0x00007f53f670a85f in clone () from /lib64/libc.so.6

Thread 4 (Thread 0x7f53d6527700 (LWP 28238)):
#0  0x00007f53f66fbba8 in read () from /lib64/libc.so.6
#1  0x00007f53efb63d20 in ?? () from /usr/lib64/libglib-2.0.so.0
#2  0x00007f53efb1ed38 in g_main_context_check () from /usr/lib64/libglib-2.0.so.0
#3  0x00007f53efb1f1d0 in ?? () from /usr/lib64/libglib-2.0.so.0
#4  0x00007f53efb1f33c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#5  0x00007f53f726651b in QEventDispatcherGlib::processEvents (this=0x7f53c8000b10, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#6  0x00007f53f7206baa in QEventLoop::exec (this=this@entry=0x7f53d6526cb0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#7  0x00007f53f7022dba in QThread::exec (this=<optimized out>) at thread/qthread.cpp:531
#8  0x00007f53f7024562 in QThreadPrivate::start (arg=0x564992aa67e0) at thread/qthread_unix.cpp:360
#9  0x00007f53f2813569 in start_thread () from /lib64/libpthread.so.0
#10 0x00007f53f670a85f in clone () from /lib64/libc.so.6

Thread 3 (Thread 0x7f53d6f73700 (LWP 28237)):
#0  0x00007f53f66fbba8 in read () from /lib64/libc.so.6
#1  0x00007f53efb63d20 in ?? () from /usr/lib64/libglib-2.0.so.0
#2  0x00007f53efb1ed38 in g_main_context_check () from /usr/lib64/libglib-2.0.so.0
#3  0x00007f53efb1f1d0 in ?? () from /usr/lib64/libglib-2.0.so.0
#4  0x00007f53efb1f33c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#5  0x00007f53f726651b in QEventDispatcherGlib::processEvents (this=0x7f53d0000b10, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#6  0x00007f53f7206baa in QEventLoop::exec (this=this@entry=0x7f53d6f72c80, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#7  0x00007f53f7022dba in QThread::exec (this=<optimized out>) at thread/qthread.cpp:531
#8  0x00007f53f90d2e35 in ?? () from /usr/lib64/libQt5DBus.so.5
#9  0x00007f53f7024562 in QThreadPrivate::start (arg=0x7f53f934ad80) at thread/qthread_unix.cpp:360
#10 0x00007f53f2813569 in start_thread () from /lib64/libpthread.so.0
#11 0x00007f53f670a85f in clone () from /lib64/libc.so.6

Thread 2 (Thread 0x7f53e4680700 (LWP 28236)):
#0  0x00007f53f67000bb in poll () from /lib64/libc.so.6
#1  0x00007f53f1e58387 in ?? () from /usr/lib64/libxcb.so.1
#2  0x00007f53f1e59fba in xcb_wait_for_event () from /usr/lib64/libxcb.so.1
#3  0x00007f53e7474898 in ?? () from /usr/lib64/libQt5XcbQpa.so.5
#4  0x00007f53f7024562 in QThreadPrivate::start (arg=0x564992872ec0) at thread/qthread_unix.cpp:360
#5  0x00007f53f2813569 in start_thread () from /lib64/libpthread.so.0
#6  0x00007f53f670a85f in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7f53fbb7e900 (LWP 28235)):
[KCrash Handler]
#6  QString::QString (other=..., this=this@entry=0x7fff103b45f0) at /usr/include/qt5/QtCore/qstring.h:955
#7  Akonadi::Item::remoteId (this=this@entry=0x7fff103b4810) at /usr/src/debug/akonadi-server-19.04.2-lp150.188.3.x86_64/src/core/item.cpp:187
#8  0x00007f53fb4d2ebb in Akonadi::ResourceBasePrivate::itemRemoved (this=0x564992b37fd0, item=...) at /usr/src/debug/akonadi-server-19.04.2-lp150.188.3.x86_64/src/agentbase/resourcebase.cpp:329
#9  0x00007f53f72393ff in QtPrivate::QSlotObjectBase::call (a=0x7fff103b4730, r=0x564992b37fd0, this=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:394
#10 QMetaObject::activate (sender=0x564992aa4210, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=7, argv=<optimized out>, argv@entry=0x7fff103b4730) at kernel/qobject.cpp:3787
#11 0x00007f53f72399a7 in QMetaObject::activate (sender=<optimized out>, m=m@entry=0x7f53faa1d9c0 <Akonadi::Monitor::staticMetaObject>, local_signal_index=local_signal_index@entry=7, argv=argv@entry=0x7fff103b4730) at kernel/qobject.cpp:3658
#12 0x00007f53fa6bbc45 in Akonadi::Monitor::itemRemoved (this=<optimized out>, _t1=...) at /usr/src/debug/akonadi-server-19.04.2-lp150.188.3.x86_64/build/src/core/KF5AkonadiCore_autogen/include/moc_monitor.cpp:951
#13 0x00007f53fa6c8a71 in Akonadi::MonitorPrivate::emitToListeners<void (Akonadi::Monitor::*)(Akonadi::Item const&), Akonadi::Item> (signal=<optimized out>, this=0x564992a8c3a0) at /usr/src/debug/akonadi-server-19.04.2-lp150.188.3.x86_64/src/core/monitor_p.h:404
#14 Akonadi::MonitorPrivate::emitItemsNotification (this=this@entry=0x564992a8c3a0, msg_=..., items=..., collection=..., collectionDest=...) at /usr/src/debug/akonadi-server-19.04.2-lp150.188.3.x86_64/src/core/monitor_p.cpp:1075
#15 0x00007f53fa6c9b1a in Akonadi::MonitorPrivate::emitNotification (this=this@entry=0x564992a8c3a0, msg=...) at /usr/src/debug/akonadi-server-19.04.2-lp150.188.3.x86_64/src/core/monitor_p.cpp:556
#16 0x00007f53fa671f5e in Akonadi::ChangeRecorderPrivate::emitNotification (this=0x564992a8c3a0, msg=...) at /usr/src/debug/akonadi-server-19.04.2-lp150.188.3.x86_64/src/core/changerecorder_p.cpp:238
#17 0x00007f53fa6cbafd in Akonadi::MonitorPrivate::flushPipeline (this=this@entry=0x564992a8c3a0) at /usr/src/debug/akonadi-server-19.04.2-lp150.188.3.x86_64/src/core/monitor_p.cpp:981
#18 0x00007f53fa6cc249 in Akonadi::MonitorPrivate::dataAvailable (this=0x564992a8c3a0) at /usr/src/debug/akonadi-server-19.04.2-lp150.188.3.x86_64/src/core/monitor_p.cpp:990
#19 0x00007f53f72392e5 in QMetaObject::activate (sender=sender@entry=0x564992ab27c0, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=0, argv=<optimized out>, argv@entry=0x0) at kernel/qobject.cpp:3807
#20 0x00007f53f72399a7 in QMetaObject::activate (sender=sender@entry=0x564992ab27c0, m=m@entry=0x7f53faa1d240 <Akonadi::EntityCacheBase::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3658
#21 0x00007f53fa6a01b0 in Akonadi::EntityCacheBase::dataAvailable (this=this@entry=0x564992ab27c0) at /usr/src/debug/akonadi-server-19.04.2-lp150.188.3.x86_64/build/src/core/KF5AkonadiCore_autogen/include/moc_entitycache_p.cpp:152
#22 0x00007f53fa66dc9a in Akonadi::EntityCache<Akonadi::Collection, Akonadi::CollectionFetchJob, Akonadi::CollectionFetchScope>::processResult (this=0x564992ab27c0, job=<optimized out>) at /usr/src/debug/akonadi-server-19.04.2-lp150.188.3.x86_64/src/core/entitycache_p.h:215
#23 0x00007f53f72392e5 in QMetaObject::activate (sender=sender@entry=0x5649929ddea0, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=3, argv=<optimized out>, argv@entry=0x7fff103b4d00) at kernel/qobject.cpp:3807
#24 0x00007f53f72399a7 in QMetaObject::activate (sender=sender@entry=0x5649929ddea0, m=m@entry=0x7f53f85ee500 <KJob::staticMetaObject>, local_signal_index=local_signal_index@entry=3, argv=argv@entry=0x7fff103b4d00) at kernel/qobject.cpp:3658
#25 0x00007f53f83907dc in KJob::result (this=this@entry=0x5649929ddea0, _t1=<optimized out>, _t1@entry=0x5649929ddea0, _t2=...) at /usr/src/debug/kcoreaddons-5.59.0-lp150.199.1.x86_64/build/src/lib/KF5CoreAddons_autogen/include/moc_kjob.cpp:574
#26 0x00007f53f8391311 in KJob::finishJob (this=0x5649929ddea0, emitResult=<optimized out>) at /usr/src/debug/kcoreaddons-5.59.0-lp150.199.1.x86_64/src/lib/jobs/kjob.cpp:109
#27 0x00007f53f7246054 in QtPrivate::QSlotObjectBase::call (a=0x7fff103b4d60, r=<optimized out>, this=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qobjectdefs_impl.h:394
#28 QSingleShotTimer::timerEvent (this=0x5649929c48e0) at kernel/qtimer.cpp:318
#29 0x00007f53f7239dfb in QObject::event (this=0x5649929c48e0, e=<optimized out>) at kernel/qobject.cpp:1282
#30 0x00007f53f876601c in QApplicationPrivate::notify_helper (this=this@entry=0x564992850d50, receiver=receiver@entry=0x5649929c48e0, e=e@entry=0x7fff103b50a0) at kernel/qapplication.cpp:3740
#31 0x00007f53f876d590 in QApplication::notify (this=0x7fff103b5390, receiver=0x5649929c48e0, e=0x7fff103b50a0) at kernel/qapplication.cpp:3486
#32 0x00007f53f7208988 in QCoreApplication::notifyInternal2 (receiver=0x5649929c48e0, event=0x7fff103b50a0) at kernel/qcoreapplication.cpp:1065
#33 0x00007f53f7265989 in QTimerInfoList::activateTimers (this=0x5649928c20b0) at kernel/qtimerinfo_unix.cpp:643
#34 0x00007f53f7266151 in timerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:183
#35 0x00007f53efb1ef07 in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
#36 0x00007f53efb1f2b0 in ?? () from /usr/lib64/libglib-2.0.so.0
#37 0x00007f53efb1f33c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#38 0x00007f53f72664ff in QEventDispatcherGlib::processEvents (this=0x5649928cb080, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#39 0x00007f53f7206baa in QEventLoop::exec (this=this@entry=0x7fff103b52f0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#40 0x00007f53f720fe60 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1373
#41 0x00007f53fb4c763d in Akonadi::ResourceBase::init (r=0x5649928dbc60) at /usr/src/debug/akonadi-server-19.04.2-lp150.188.3.x86_64/src/agentbase/resourcebase.cpp:608
#42 0x000056499161ebe3 in Akonadi::ResourceBase::init<DavGroupwareResource> (argc=<optimized out>, argv=<optimized out>) at /usr/include/KF5/AkonadiAgentBase/resourcebase.h:199
#43 0x00007f53f6632f8a in __libc_start_main () from /lib64/libc.so.6
#44 0x00005649915dfc3a in _start () at ../sysdeps/x86_64/start.S:120
[Inferior 1 (process 28235) detached]