Bug 413696

SUMMARY
I have a Ethernet network connection with auto connect enabled and "Available to all users" checked, i.e., it's part of `/etc/NetworkManager/system-connections`, which means NetworkManager will automatically connect to the network before login from display manager (SDDM in my case). It works well, I can confirm my PC is online before login. However, right after login plasma-nm disconnects from it and reconnects right after that, I can even see the notification of connection status changed. This is obviously redundant and leads to bad UX, please fix it, thanks.

STEPS TO REPRODUCE
1. Create a network connection from plasma-nm GUI, check "Available to all users", and make sure NetworkManager.service is enabled.
2. Reboot
3. When reaching DM greeting, ping from another PC or router to make sure it's online.
4. Login as usual

OBSERVED RESULT
The connected network disconnects and reconnects, receiving notification from plasma-nm

EXPECTED RESULT
The previous connection keeps alive

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Arch Linux
KDE Plasma Version: 5.17.2
KDE Frameworks Version: 5.63.0
Qt Version: 5.13.1

ADDITIONAL INFORMATION