Since this past weekend I'm occasionally hitting a segfault with this backtrace when viewing messages

Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00007fa687cf2660 in raise () from /usr/lib64/libc.so.6
[Current thread is 1 (Thread 0x7fa68ece3980 (LWP 28061))]
#0  0x00007fa687cf2660 in raise () at /usr/lib64/libc.so.6
#1  0x00007fa68e273879 in KCrash::defaultCrashHandler(int) (sig=11) at /data/kde/src/5/frameworks/kc
rash/src/kcrash.cpp:432
#2  0x00007fa687cf26e0 in <signal handler called> () at /usr/lib64/libc.so.6
#3  0x00007fa688bd9fa4 in QObject::disconnect(QObject const*, char const*, QObject const*, char const*) () at /usr/lib64/libQt5Core.so.5
#4  0x00007fa689817ff2 in QActionGroup::removeAction(QAction*) () at /usr/lib64/libQt5Widgets.so.5
#5  0x00007fa686ceffd2 in GrantleeTheme::ThemeManager::Private::~Private() (this=0x175d5f0, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/grantleetheme/src/grantleethememanager.cpp:90
#6  0x00007fa686cee391 in GrantleeTheme::ThemeManager::~ThemeManager() (this=0x174bfd0, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/grantleetheme/src/grantleethememanager.cpp:297
#7  0x00007fa686cee3c8 in GrantleeTheme::ThemeManager::~ThemeManager() (this=0x174bfd0, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/grantleetheme/src/grantleethememanager.cpp:298
#8  0x00007fa688bdccc8 in QObjectPrivate::deleteChildren() () at /usr/lib64/libQt5Core.so.5
#9  0x00007fa688bddba2 in QObject::~QObject() () at /usr/lib64/libQt5Core.so.5
#10 0x00007fa553930eda in MessageViewer::HeaderStyleInterface::~HeaderStyleInterface() (this=0x1792420, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/messagelib/messageviewer/src/header/headerstyleinterface.cpp:35
#11 0x00007fa535c93fbc in MessageViewer::GrantleeHeaderStyleInterface::~GrantleeHeaderStyleInterface() (this=0x1792420, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/kdepim-addons/plugins/messageviewerheaderplugins/grantleeheaderstyleplugin/grantleeheaderstyleinterface.cpp:33
#12 0x00007fa535c93fd8 in MessageViewer::GrantleeHeaderStyleInterface::~GrantleeHeaderStyleInterface() (this=0x1792420, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/kdepim-addons/plugins/messageviewerheaderplugins/grantleeheaderstyleplugin/grantleeheaderstyleinterface.cpp:35
#13 0x00007fa688bdccc8 in QObjectPrivate::deleteChildren() () at /usr/lib64/libQt5Core.so.5
#14 0x00007fa688bddba2 in QObject::~QObject() () at /usr/lib64/libQt5Core.so.5
#15 0x00007fa55393263b in MessageViewer::HeaderStyleMenuManager::~HeaderStyleMenuManager() (this=0x174dde0, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/messagelib/messageviewer/src/header/headerstylemenumanager.cpp:166
#16 0x00007fa553932656 in MessageViewer::HeaderStyleMenuManager::~HeaderStyleMenuManager() (this=0x174dde0, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/messagelib/messageviewer/src/header/headerstylemenumanager.cpp:169
#17 0x00007fa688bdccc8 in QObjectPrivate::deleteChildren() () at /usr/lib64/libQt5Core.so.5
#18 0x00007fa688bddba2 in QObject::~QObject() () at /usr/lib64/libQt5Core.so.5
#19 0x00007fa5538d5d0e in MessageViewer::ViewerPrivate::~ViewerPrivate() (this=0x169f310, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/messagelib/messageviewer/src/viewer/viewer_p.cpp:293
#20 0x00007fa5538d5d2a in MessageViewer::ViewerPrivate::~ViewerPrivate() (this=0x169f310, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/messagelib/messageviewer/src/viewer/viewer_p.cpp:304
#21 0x00007fa688bdccc8 in QObjectPrivate::deleteChildren() () at /usr/lib64/libQt5Core.so.5
#22 0x00007fa689854f84 in QWidget::~QWidget() () at /usr/lib64/libQt5Widgets.so.5
#23 0x00007fa5538cf402 in MessageViewer::Viewer::~Viewer() (this=0x169f020, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/messagelib/messageviewer/src/viewer/viewer.cpp:84
#24 0x00007fa5538cf424 in MessageViewer::Viewer::~Viewer() (this=0x169f020, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/messagelib/messageviewer/src/viewer/viewer.cpp:87
#25 0x00007fa688bdccc8 in QObjectPrivate::deleteChildren() () at /usr/lib64/libQt5Core.so.5
#26 0x00007fa689854f84 in QWidget::~QWidget() () at /usr/lib64/libQt5Widgets.so.5
#27 0x00007fa5556baccc in KMReaderWin::~KMReaderWin() (this=0x1693d10, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/kmail/src/kmreaderwin.cpp:226
#28 0x00007fa5556bacee in KMReaderWin::~KMReaderWin() (this=0x1693d10, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/kmail/src/kmreaderwin.cpp:228
#29 0x00007fa688bdccc8 in QObjectPrivate::deleteChildren() () at /usr/lib64/libQt5Core.so.5
#30 0x00007fa689854f84 in QWidget::~QWidget() () at /usr/lib64/libQt5Widgets.so.5
#31 0x00007fa6899c4269 in QSplitter::~QSplitter() () at /usr/lib64/libQt5Widgets.so.5
#32 0x00007fa688bdccc8 in QObjectPrivate::deleteChildren() () at /usr/lib64/libQt5Core.so.5
#33 0x00007fa689854f84 in QWidget::~QWidget() () at /usr/lib64/libQt5Widgets.so.5
#34 0x00007fa6899c4269 in QSplitter::~QSplitter() () at /usr/lib64/libQt5Widgets.so.5
#35 0x00007fa555708815 in KMMainWidget::deleteWidgets() (this=0x15b9db0) at /data/kde/src/5/kde/pim/kmail/src/kmmainwidget.cpp:972
#36 0x00007fa5557062ed in KMMainWidget::destruct() (this=0x15b9db0) at /data/kde/src/5/kde/pim/kmail/src/kmmainwidget.cpp:377
#37 0x00007fa555b86e7d in KMailPart::~KMailPart() (this=0x1367270, __in_chrg=<optimized out>, __vtt_parm=<optimized out>) at /data/kde/src/5/kde/pim/kmail/src/kmail_part.cpp:110
#38 0x00007fa555b86efe in KMailPart::~KMailPart() (this=0x1367270, __in_chrg=<optimized out>, __vtt_parm=<optimized out>) at /data/kde/src/5/kde/pim/kmail/src/kmail_part.cpp:113
#39 0x00007fa68e48b8b5 in KontactInterface::Plugin::~Plugin() (this=0x13ada30, __vtt_parm=0x7fa5563ee118 <VTT for KMailPlugin+8>, __in_chrg=<optimized out>) at /data/kde/src/5/kde/pim/kontactinterface/src/plugin.cpp:89
#40 0x00007fa5561d3bf1 in KMailPlugin::~KMailPlugin() (this=0x13ada30, __in_chrg=<optimized out>, __vtt_parm=<optimized out>) at /data/kde/src/5/kde/pim/kmail/src/kontactplugin/kmail/kmail_plugin.cpp:172
#41 0x00007fa5561d3c28 in KMailPlugin::~KMailPlugin() (this=0x13ada30, __in_chrg=<optimized out>, __vtt_parm=<optimized out>) at /data/kde/src/5/kde/pim/kmail/src/kontactplugin/kmail/kmail_plugin.cpp:176
#42 0x00007fa68e6bc7d7 in Kontact::MainWindow::~MainWindow() (this=0x11d4ce0, __in_chrg=<optimized out>, __vtt_parm=<optimized out>) at /data/kde/src/5/kde/pim/kontact/src/mainwindow.cpp:292
#43 0x00007fa68e6bc8fa in Kontact::MainWindow::~MainWindow() (this=0x11d4ce0, __in_chrg=<optimized out>, __vtt_parm=<optimized out>) at /data/kde/src/5/kde/pim/kontact/src/mainwindow.cpp:294
#44 0x00007fa688bd7288 in QObject::event(QEvent*) () at /usr/lib64/libQt5Core.so.5
#45 0x00007fa689859953 in QWidget::event(QEvent*) () at /usr/lib64/libQt5Widgets.so.5
#46 0x00007fa68996d59b in QMainWindow::event(QEvent*) () at /usr/lib64/libQt5Widgets.so.5
#47 0x00007fa68ca7e03b in KMainWindow::event(QEvent*) (this=0x11d4ce0, ev=0x3631a50) at /data/kde/src/5/frameworks/kxmlgui/src/kmainwindow.cpp:865
#48 0x00007fa68cabfc0a in KXmlGuiWindow::event(QEvent*) (this=0x11d4ce0, ev=0x3631a50) at /data/kde/src/5/frameworks/kxmlgui/src/kxmlguiwindow.cpp:119
#49 0x00007fa68981a92c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib64/libQt5Widgets.so.5
#50 0x00007fa689822174 in QApplication::notify(QObject*, QEvent*) () at /usr/lib64/libQt5Widgets.so.5
#51 0x00007fa688badbe7 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib64/libQt5Core.so.5
#52 0x00007fa688bb036b in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib64/libQt5Core.so.5
#53 0x00007fa688bfee43 in postEventSourceDispatch(_GSource*, int (*)(void*), void*) () at /usr/lib64/libQt5Core.so.5
#54 0x00007fa677de4b77 in g_main_context_dispatch () at /usr/lib64/libglib-2.0.so.0
#55 0x00007fa677de4f20 in g_main_context_iterate.isra () at /usr/lib64/libglib-2.0.so.0
#56 0x00007fa677de4fac in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#57 0x00007fa688bfec2f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#58 0x00007fa688bac96a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#59 0x00007fa688bb5094 in QCoreApplication::exec() () at /usr/lib64/libQt5Core.so.5
#60 0x00000000004059e7 in  ()
#61 0x00007ffce2964628 in  ()
#62 0x0000000100000160 in  ()
#63 0x0000000000408208 in  ()
#64 0x00000000011957f0 in  ()
#65 0x0000000001164250 in  ()
#66 0x0000000001163ad0 in  ()
#67 0x000000000060bb00 in  ()
#68 0x0000000000e09680 in  ()
#69 0x0000000001160d90 in  ()
#70 0x0000000001376450 in  ()
#71 0x00000000011d4ce0 in  ()
#72 0x0000ffff00001f00 in  ()
#73 0x00000000004086a0 in  ()
#74 0x00007fa687cc6c30 in  () at /usr/lib64/libc.so.6
#75 0x000000000115fef0 in  ()
#76 0x00000000004086e0 in  ()
#77 0x0000000000000001 in  ()
#78 0x0000000000408720 in  ()
#79 0x00007fa68e8f00a0 in __dso_handle () at /data/kde/inst/5/lib64/libkontactprivate.so.5
#80 0x0000000001171d00 in  ()
#81 0x0000000000408760 in  ()
#82 0x00007fa68806ec20 in main_arena () at /usr/lib64/libc.so.6
#83 0x0000000000408e40 in  ()
#84 0x0000000000000000 in  ()