Running Kubuntu 16.04 with kubuntu-backports PPA enabled.

$ konsole --version
QCoreApplication::arguments: Please instantiate the QApplication object first
Qt: 5.5.1
KDE Frameworks: 5.18.0
Konsole: 15.12.3

Steps to reproduce: 

1. Open Konsole
2. Sleep the machine
3. Wake up. 
4. Attempt to close the konsole window with the 'x' in the title bar. 
5. The 'confirm close -- Konsole' window appears, but with no content. 

Attaching GDB to the process, I see that the main dispatch thread is blocked on a condition variable at: 

#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:143
#1  0x00007f7fc207ce48 in pa_threaded_mainloop_wait () from /usr/lib/x86_64-linux-gnu/libpulse.so.0
#2  0x00007f7fa76fff3f in ?? () from /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstpulse.so
#3  0x00007f7fabb6519b in gst_audio_ring_buffer_open_device () from /usr/lib/x86_64-linux-gnu/libgstaudio-1.0.so.0
#4  0x00007f7fabb84db9 in ?? () from /usr/lib/x86_64-linux-gnu/libgstaudio-1.0.so.0
#5  0x00007f7fa7703802 in ?? () from /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstpulse.so
#6  0x00007f7facbb61ce in gst_element_change_state (element=element@entry=0x2d15080, transition=transition@entry=GST_STATE_CHANGE_NULL_TO_READY) at gstelement.c:2648
#7  0x00007f7facbb6947 in gst_element_set_state_func (element=0x2d15080, state=GST_STATE_READY) at gstelement.c:2602
#8  0x00007f7facea5798 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/phonon4qt5_backend/phonon_gstreamer.so
#9  0x00007f7facea5bbf in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/phonon4qt5_backend/phonon_gstreamer.so
#10 0x00007f7facea7562 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/phonon4qt5_backend/phonon_gstreamer.so
#11 0x00007f7facea8680 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/phonon4qt5_backend/phonon_gstreamer.so
#12 0x00007f7facea026c in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/phonon4qt5_backend/phonon_gstreamer.so
#13 0x00007f7facea06a8 in qt_plugin_instance () from /usr/lib/x86_64-linux-gnu/qt5/plugins/phonon4qt5_backend/phonon_gstreamer.so
#14 0x00007f7fc9c09abf in QPluginLoader::instance() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#15 0x00007f7fc7f64398 in ?? () from /usr/lib/x86_64-linux-gnu/libphonon4qt5.so.4
#16 0x00007f7fc7f667e7 in ?? () from /usr/lib/x86_64-linux-gnu/libphonon4qt5.so.4
#17 0x00007f7fc7f66a11 in ?? () from /usr/lib/x86_64-linux-gnu/libphonon4qt5.so.4
#18 0x00007f7fc7f672c0 in Phonon::Factory::backend(bool) () from /usr/lib/x86_64-linux-gnu/libphonon4qt5.so.4
#19 0x00007f7fc7f677e3 in ?? () from /usr/lib/x86_64-linux-gnu/libphonon4qt5.so.4
#20 0x00007f7fc7f5dde9 in ?? () from /usr/lib/x86_64-linux-gnu/libphonon4qt5.so.4
#21 0x00007f7fc7f5a8cf in ?? () from /usr/lib/x86_64-linux-gnu/libphonon4qt5.so.4
#22 0x00007f7fc94016a2 in ?? () from /usr/lib/x86_64-linux-gnu/libKF5Notifications.so.5
#23 0x00007f7fc93e5e96 in ?? () from /usr/lib/x86_64-linux-gnu/libKF5Notifications.so.5
#24 0x00007f7fc93e3598 in KNotification::sendEvent() () from /usr/lib/x86_64-linux-gnu/libKF5Notifications.so.5
#25 0x00007f7fc9c4fc01 in QObject::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#26 0x00007f7fca51305c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#27 0x00007f7fca518516 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#28 0x00007f7fc9c2038b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#29 0x00007f7fc9c22786 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#30 0x00007f7fc9c763c3 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#31 0x00007f7fc4e2d197 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#32 0x00007f7fc4e2d3f0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#33 0x00007f7fc4e2d49c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#34 0x00007f7fc9c767cf in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#35 0x00007f7fc9c1db4a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#36 0x00007f7fca70dd8d in QDialog::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#37 0x00007f7fcad84e59 in KMessageBox::createKMessageBox(QDialog*, QDialogButtonBox*, QIcon const&, QString const&, QStringList const&, QString const&, bool*, QFlags<KMessageBox::Option>, QString const&, QMessageBox::Icon) ()
   from /usr/lib/x86_64-linux-gnu/libKF5WidgetsAddons.so.5
#38 0x00007f7fcad85538 in KMessageBox::createKMessageBox(QDialog*, QDialogButtonBox*, QMessageBox::Icon, QString const&, QStringList const&, QString const&, bool*, QFlags<KMessageBox::Option>, QString const&) ()
   from /usr/lib/x86_64-linux-gnu/libKF5WidgetsAddons.so.5
#39 0x00007f7fcad87c2c in ?? () from /usr/lib/x86_64-linux-gnu/libKF5WidgetsAddons.so.5
#40 0x00007f7fcd3876bc in ?? () from /usr/lib/x86_64-linux-gnu/libkdeinit5_konsole.so
#41 0x00007f7fcc37ef15 in KMainWindow::closeEvent(QCloseEvent*) () from /usr/lib/x86_64-linux-gnu/libKF5XmlGui.so.5
#42 0x00007f7fca555fc8 in QWidget::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#43 0x00007f7fca66bdbb in QMainWindow::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#44 0x00007f7fcc37f147 in KMainWindow::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libKF5XmlGui.so.5
#45 0x00007f7fcc3b74e5 in KXmlGuiWindow::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libKF5XmlGui.so.5
#46 0x00007f7fca51305c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#47 0x00007f7fca518516 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#48 0x00007f7fc9c2038b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#49 0x00007f7fca5512bd in QWidgetPrivate::close_helper(QWidgetPrivate::CloseMode) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#50 0x00007f7fca572cc2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#51 0x00007f7fca51305c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#52 0x00007f7fca518516 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#53 0x00007f7fc9c2038b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#54 0x00007f7fc9f5f67e in QGuiApplicationPrivate::processCloseEvent(QWindowSystemInterfacePrivate::CloseEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#55 0x00007f7fc9f641d5 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#56 0x00007f7fc9f47f08 in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#57 0x00007f7fbab09200 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#58 0x00007f7fc4e2d197 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#59 0x00007f7fc4e2d3f0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
---Type <return> to continue, or q <return> to quit---
#60 0x00007f7fc4e2d49c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#61 0x00007f7fc9c767cf in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#62 0x00007f7fc9c1db4a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#63 0x00007f7fc9c25bec in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#64 0x00007f7fcd393d92 in kdemain () from /usr/lib/x86_64-linux-gnu/libkdeinit5_konsole.so
#65 0x00007f7fccfc2830 in __libc_start_main (main=0x400710 <main>, argc=1, argv=0x7fff26b543c8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff26b543b8) at ../csu/libc-start.c:291
#66 0x0000000000400749 in _start ()