yumex-dnf and dnfdaemon locking issues

[genodeftest]

I'm sometimes running in yumex-dnf being unable to connect to dnf-daemon. Some symptoms:

When starting yumex-dnf I get an error message dialog:

dnf is locked by another process 

Yum Extender will exit

While this happens, the yumex-dnf-updatechecker process is running. stacktrace from attaching gdb to the running instance:

Traceback (most recent call first):
  File "/usr/lib/python3.5/site-packages/yumex/updater.py", line 270, in on_activate
    Gtk.main()
  File "/usr/lib/python3.5/site-packages/yumex/updater.py", line 307, in on_command_line
    self.activate()
  File "/usr/bin/yumex-dnf-updatechecker", line 40, in <module>
    exit_status = app.run(sys.argv)

yumex-dnf-updatechecker has a child process, yumex-dnf, which is in zombie state.

From this state there is nothing I can do except terminating dnfdaemon-system.

dnfdaemon-system (running as root), attached to gdb:

Traceback (most recent call first):
  File "/usr/lib64/python3.5/site-packages/gi/overrides/GLib.py", line 573, in run
    super(MainLoop, self).run()
  File "/usr/lib/python3.5/site-packages/dnfdaemon/server/__init__.py", line 1091, in mainloop_run
    MAINLOOP.run()
  File "/usr/share/dnfdaemon/dnfdaemon-system", line 761, in main
    yd.mainloop_run()
  File "/usr/share/dnfdaemon/dnfdaemon-system", line 765, in <module>
    main()