First error appeared during update:
The screen locker is broken and unlocking is not possible anymore. In order to unlock switch to a virtual terminal (e.g. Ctrl+Alt+F2), log in and execute the command: loginctl unlock-session 3 Then log out of the virtual session by pressing Ctrl+D, and switch back to the running session (Ctrl+Alt+F7)
Second error appeared after update:
warning: manjaro-hello: local (0.7.0-6) is newer than extra (0.7.0-5)
In the Plasma edition of Manjaro, the GUI session runs at tty1, not at tty7 (as in many other distributions), so the shortcut to return to the GUI session from any tty login session would be Alt+F1, not (Ctrl+)Alt+F7. 
Ah yes… The manjaro-hello package was upgraded to 0.7.0.-6 at some point, but this update was pulled from the repo again later, and so you need to downgrade the package again — or at least, if it causes you problems, that is.
In order to allow downgrading, use the following command… 
sudo pacman -Syuu
Note the uu in the pacman option above; that’s what allows downgrading.
Everything works fine and I will leave manjaro-hello as it is, I am not a fan of downgrading anything. Also lock screen is working fine after restart. 
Despite 2 mentioned errors everything is working fine. I will leave manjaro-hello as it is, I am not a fan of downgrading anything. Also lock screen is working fine after restart.
You can safely downgrade it. I even uninstalled manjaro-hello 0.7.0-6 with pacman -R, reinstalled 0.7.0-5 and no problem at all. Manjaro-hello is merely a menu:
I know what manjaro-hello is. Thanks for the suggestion, but I will stick to the newer version. It works fine with 0.7.0-6 version and it will be updated eventually anyway and warning will disappear, but thanks anyway.
