Of course, I understand it, that’s the reason why this topic exists.
My Manjaro “looks strange” on the login screen too, when I don’t even log in into my user profile. So it cannot be the problem linked with widgets, customization, or theme! It is a problem with some package that was not correctly installed during the last big update to Plasma 6. Maybe am I wrong? You can feel free to correct me and my suggestions.
You wrote in your topic ([root tip] [How To] Update Manjaro the smart way):
Don’t ever interrupt the process
But my process of upgrading the system was interrupted by broken PGP keys. I didn’t want it, but it happened.