I just installed the KDE Neon LTS 5.8 system on my PC.
With the new system the wire network connection is not established on startup.
I had the same configuration using Kubuntu 16.04 and it worked fine.
When connecting manually (via tray icon) it works properly (including auto-connect of the configured VPN) so I think the network configuration is ok.
However it seems some other component (that should establish the connection after restart) doesn't work.
Of course the option "Automatically connect when available" (translated from german) is enabled as well as the option "All user are allowed to connect with the network" (translated from german).
What could be the reason and how can I check it?