Application: DiscoverNotifier (5.27.9)

Qt Version: 5.15.11
Frameworks Version: 5.111.0
Operating System: Linux 6.2.9-300.fc38.x86_64 x86_64
Windowing System: X11
Distribution: Fedora Linux 39 (KDE Plasma)
DrKonqi: 5.27.9 [KCrashBackend]

-- Information about the crash:
Fresh install of Fedora38's KDE system. On starting the DE (Plasma X11), I get a discover notifier about a crash, and nothing KDE-related appears to start (no panel, no background. The only exception is this crash handler, and the "welcome to KDE Plasma" dialog.). 
I cannot figure out how to start any applications (RMB does nothing, ALT+F1 does nothing, ALT+F2 gets the "search" dropdown (KRunner?), but any keyboard press causes it to disappear again. TTY works, and that way I ran a system-upgrade to Fedora 39. It behaves identically.
I also tried Plasma Wayland (after login, I get a black screen with nothing but a mouse pointer - for about one second. After that, it switches to what looks like a non-graphical window for one second until the black screen with the mouse pointer reappears. Repeat ad infinitum).
Fair to be said that this might be unrelated to KDE: I have the same problem and symptoms in XFCE (but not in LXDE). I have yet to install and try Gnome.

The crash can be reproduced every time.

-- Backtrace:
Application: Discover Notifier (DiscoverNotifier), signal: Segmentation fault

[KCrash Handler]
#4  0x00007f92601bbdd5 in flatpak_installation_create_monitor () from /lib64/libflatpak.so.0
#5  0x00007f9260d75035 in FlatpakNotifier::Installation::ensureInitialized(std::function<_FlatpakInstallation* ()>, _GCancellable*, _GError**) () from /usr/lib64/qt5/plugins/discover-notifier/FlatpakNotifier.so
#6  0x00007f9260d7551b in FlatpakNotifier::recheckSystemUpdateNeeded() () from /usr/lib64/qt5/plugins/discover-notifier/FlatpakNotifier.so
#7  0x00005631e8f0de55 in DiscoverNotifier::recheckSystemUpdateNeeded() ()
#8  0x00007f927bedf11b in QObject::event(QEvent*) () from /lib64/libQt5Core.so.5
#9  0x00007f927cbaeb75 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib64/libQt5Widgets.so.5
#10 0x00007f927beb4598 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /lib64/libQt5Core.so.5
#11 0x00007f927beb7a45 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /lib64/libQt5Core.so.5
#12 0x00007f927bf06fef in postEventSourceDispatch(_GSource*, int (*)(void*), void*) () from /lib64/libQt5Core.so.5
#13 0x00007f927a512e5c in g_main_context_dispatch_unlocked.lto_priv () from /lib64/libglib-2.0.so.0
#14 0x00007f927a56ddd8 in g_main_context_iterate_unlocked.isra () from /lib64/libglib-2.0.so.0
#15 0x00007f927a510ad3 in g_main_context_iteration () from /lib64/libglib-2.0.so.0
#16 0x00007f927bf06ad9 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQt5Core.so.5
#17 0x00007f927beb2f5b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQt5Core.so.5
#18 0x00007f927bebb1eb in QCoreApplication::exec() () from /lib64/libQt5Core.so.5
#19 0x00005631e8f099d7 in main ()
[Inferior 1 (process 2284) detached]

The reporter indicates this bug may be a duplicate of or related to bug 467012, bug 463070.

Reported using DrKonqi