I have two opensuse TW (DE plasma 5)and I noticed that both of them don’t let me edit Networkmanager wired connections. The “Apply” button is always greyed out however I edit the connection. If I just OK out, then no change can be saved when you open it up.
If I do need to make some configuration changes to a connection. I have to create a new wired connection and set it up the way I need and delete the old one.
Nonetheless, editing wifi connection works fine. Some privileged requirement prompt would pop up when I edit.