SUMMARY
I updated my Frameworks to 5.60.0 and applications to 19.04.3. I shut down my laptop and restarted once, and everything went fine. the second time, with an external screen attached, I got a crash of ksplashqml on startup. Apart from the crash message, everything seems to work fine.

STEPS TO REPRODUCE
Not yet tried.

OBSERVED RESULT
ksplashqml crashes

EXPECTED RESULT
? (I do not know what ksplashqml's function is.)

SOFTWARE/OS VERSIONS
Linux: 4.19.57 
KDE Plasma Version: 5.15.5
KDE Frameworks Version: 5.60.0
Qt Version: 5.12.3
xf86-video-intel: 2.99.917_p20190301

ADDITIONAL INFORMATION

Application: ksplashqml (ksplashqml), signal: Aborted
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f54176ce880 (LWP 4450))]

Thread 2 (Thread 0x7f540e700700 (LWP 4452)):
#0  std::__atomic_base<QMutexData*>::compare_exchange_strong (__m2=std::memory_order_acquire, __m1=std::memory_order_acquire, __p2=0x1, __p1=<synthetic pointer>: 0x0, this=this@entry=0x558751a09a10) at /usr/lib/gcc/x86_64-pc-linux-gnu/8.3.0/include/g++-v8/bits/atomic_base.h:742
#1  std::atomic<QMutexData*>::compare_exchange_strong (__m2=std::memory_order_acquire, __m1=std::memory_order_acquire, __p2=0x1, __p1=<synthetic pointer>: 0x0, this=this@entry=0x558751a09a10) at /usr/lib/gcc/x86_64-pc-linux-gnu/8.3.0/include/g++-v8/atomic:498
#2  QAtomicOps<QMutexData*>::testAndSetAcquire<QMutexData*> (currentValue=<synthetic pointer>, newValue=0x1, expectedValue=0x0, _q_value=...) at ../../include/QtCore/../../src/corelib/thread/qatomic_cxx11.h:290
#3  QBasicAtomicPointer<QMutexData>::testAndSetAcquire (currentValue=<synthetic pointer>: <optimized out>, newValue=0x1, expectedValue=0x0, this=this@entry=0x558751a09a10) at ../../include/QtCore/../../src/corelib/thread/qbasicatomic.h:263
#4  QBasicMutex::fastTryLock (current=<synthetic pointer>: <optimized out>, this=this@entry=0x558751a09a10) at thread/qmutex.h:107
#5  QMutex::lock (this=this@entry=0x558751a09a10) at thread/qmutex.cpp:222
#6  0x00007f541e6839ef in QMutexLocker::QMutexLocker (m=0x558751a09a10, this=<synthetic pointer>) at ../../include/QtCore/../../src/corelib/thread/qmutex.h:206
#7  QThreadData::canWaitLocked (this=0x558751a099e0) at ../../include/QtCore/5.12.3/QtCore/private/../../../../../src/corelib/thread/qthread_p.h:269
#8  postEventSourcePrepare (s=0x7f5408004ba0, timeout=0x7f540e6ffb14) at kernel/qeventdispatcher_glib.cpp:259
#9  0x00007f541bddc0a9 in g_main_context_prepare () from /usr/lib64/libglib-2.0.so.0
#10 0x00007f541bddcaab in ?? () from /usr/lib64/libglib-2.0.so.0
#11 0x00007f541bddcc9c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#12 0x00007f541e683afb in QEventDispatcherGlib::processEvents (this=0x7f5408000b20, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#13 0x00007f541e63193b in QEventLoop::exec (this=this@entry=0x7f540e6ffcf0, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:140
#14 0x00007f541e4a43d6 in QThread::exec (this=<optimized out>) at ../../include/QtCore/../../src/corelib/global/qflags.h:120
#15 0x00007f541edf9565 in ?? () from /usr/lib64/libQt5DBus.so.5
#16 0x00007f541e4a5602 in QThreadPrivate::start (arg=0x7f541ee79d80) at thread/qthread_unix.cpp:361
#17 0x00007f541c6d6408 in start_thread () from /lib64/libpthread.so.0
#18 0x00007f541e111adf in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7f54176ce880 (LWP 4450)):
[KCrash Handler]
#6  0x00007f541e043f6b in raise () from /lib64/libc.so.6
#7  0x00007f541e02d535 in abort () from /lib64/libc.so.6
#8  0x00007f541e089cc9 in ?? () from /lib64/libc.so.6
#9  0x00007f541e091b38 in ?? () from /lib64/libc.so.6
#10 0x00007f541e0935d7 in ?? () from /lib64/libc.so.6
#11 0x00007f541eca5d80 in QCache<QByteArray, QOpenGLProgramBinaryCache::MemCacheEntry>::clear (this=0x7f541ede29f0 <QOpenGLShaderProgramPrivate::linkBinary()::binCache+16>) at /usr/lib/gcc/x86_64-pc-linux-gnu/8.3.0/include/g++-v8/bits/atomic_base.h:303
#12 QCache<QByteArray, QOpenGLProgramBinaryCache::MemCacheEntry>::~QCache (this=0x7f541ede29f0 <QOpenGLShaderProgramPrivate::linkBinary()::binCache+16>, __in_chrg=<optimized out>) at ../../include/QtCore/../../src/corelib/tools/qcache.h:93
#13 QOpenGLProgramBinaryCache::~QOpenGLProgramBinaryCache (this=0x7f541ede29e0 <QOpenGLShaderProgramPrivate::linkBinary()::binCache>, __in_chrg=<optimized out>) at opengl/qopenglprogrambinarycache_p.h:60
#14 0x00007f541e046bc8 in ?? () from /lib64/libc.so.6
#15 0x00007f541e046d0a in exit () from /lib64/libc.so.6
#16 0x00007f541e02ef02 in __libc_start_main () from /lib64/libc.so.6
#17 0x0000558750f7995a in _start ()
[Inferior 1 (process 4450) detached]