So… I have been updating much my fedora kde.. cause well fedora.. is in between a rolling release and a Stable/Lts? but whenever I choose to update through discover and choose on the selection box to restart my notebook something feels strange… it starts the logOut sound and most apps close and doesnt open anymore (like firefox etc) but i go out… and 10 min later my notebook is still there.. frozen in the in between of doing nothing and restarting … And i notice that when i see the app tray icon for applying the update and restarting … it doesnt works… so i have to use reboot on terminal.. ;w and it wasnt happening back then when i started using Fedora kde..
It sounds like it could be this issue, where a fix will be released soon:
hi at both,
I’m the author of the Bug that @pg-tips linked. Additionally, I’ve already created a bugfix PR, which has already been merged into master.
My local patched binary is working as intended.
This however, if you read the bug info, you will notice this doesn’t actually fix the bug, but it just guards the double input that the plasma receives.
After I duck a little deeper, I’ve noticed this issue is probably coming from packagekit which it has been updated to the version 1.4.0 just a few days after the issue started appearing on my Fedora computer. I’ve created an issue also on its GitHub page but so far I haven’t got any feedback from the developers.
Fingers crossed new Plasma Workspace gets released soon with the fix 
yeah this is the discover reboot bug on recent packagekit (525911). the apps close then plasma just sits there
until the fix lands on fedora, skip the reboot checkbox in discover and reboot yourself after updates finish:
systemctl reboot
or from a tty if the session already wedged:
ctrl+alt+f3
systemctl reboot
if you want to keep using the checkbox, wait for the packagekit / plasma patch sometimes linked in that bug. the tray “apply and restart” path is the same broken path right now.