SUMMARY
Software Updates notifications stay on the screen and they can grow to larger number.
These notifications (which stay on the screen) are the most annoying feature in Linux desktop today. I am constantly forced to get rid of these notifications several times a day.
Please get rid of it. Use standard notification which disappear after some time. 

Regarding the error on the screenshot, I allowed the unverified signature in zypper, but packagekit cannot handle it. Zypper is not giving me any errors, packagekit does. It is wrong that the system uses two different platforms for updates and they are not aware of each other. This results into bad user experience!

STEPS TO REPRODUCE
1. Just use updates. Everytime update is available these notification will pop up and are glued to the screen.


OBSERVED RESULT
Notifications are glued to the screen. They don't disappear unless manually removed.


EXPECTED RESULT
Use normal notifications which disappear after few seconds.


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: openSuse Tumbleweed / Plasma 5.21.5
KDE Plasma Version: 5.21.5
KDE Frameworks Version: 5.82.0
Qt Version: 5.15.2