Pauli O,
The problem was intermittent and time dependent and also depending on the level of the Build installed. In my case only 3 out of 5 computers failed and only the ones connected via Ethernet, I never had any issue with Wi-Fi.
On Dell XPS 8300 with build 19603.1000 or 18363.753 it never fails now and I don't use any workaround, but the same machine used to fail solid with some older builds.
The MSI GT70 Laptop with build 18363.753 or 19041.173 is not failing anymore without any workaround, but used to fail on every restart with older builds.
On Dell XPS 8700 with build 18363.753 I still have Remote Desktop Enabled, I will try to disable it again to see if it still fails, perhaps with latest builds they fixed the original bug ?
Edit:
My XPS 8700 with 18363.753 still failed after a restart when I disabled Remote Desktop.
So I did another network reset and restarted a few times again, it worked fine each time, we'll see if it lasts...
It did not last, when I booted the other computer with a different code level (19603) the XPS 8700 with 18363.753 started failing again.
I re-enabled remote desktop again to work around the bug.