Hello Pulle,
we have found this issue internally. It was an issue introduced by fixing another problem.
It is resolved already and a hotfix v1.5.0f13 is on its way to fix the problem.

Thanks for reporting though, we could have easily missed that.

The issue has been fixed and hotfix v1.5.0f13 is coming soon :)

We are using an outdated Networking framework for multiplayer and it would be quite a big afford to integrate to a different one.
It works good most of the time but seems like when you play multiple hours of multiplayer sometimes the uLink framework bugs out.
When the game is restarted from time to time that should not happen.
I know that is not ideal and I hope we get in future time to switch to a new solution.

So did disabling Steam Overlay fix the issue for you?

"CoherentUI_Host.exe" is the UI process which does lag for you.

The latter would be important, since it happens often that the UI process gets assigned to the Intel GPU.
Did you try this step:
(from http://brightrockgames.userecho.com/topics/1096-missing-invisible-or-laggy-ui/)
"Forcing WFTO to use your Nvidia GPU

1. Open Nvidia control panel as above
2. Select 3D Settings and reset your settings to default
3. Select "Program Settings" tab from the 3D Settings menu
4. Add WFTOGame.exe from your WFTO Directory (You can find this by rightcliking the game in steam, going to properties and clicking "Browse local files")
5. In addition be sure to add "CoherentUI_Host.exe" with the same settings below.
6. Select "High-performance Nvidia Processor" as the preferred graphic processor as above."

?

Normally doing so fixes UI lag issues on rigs with switchable graphics.

OK should not happen anymore in hotfix v1.5.0f13

Something extremely weird must have happened with the networking components of the game.
I have never seen such errors. It looks like all units lost their network view ID.
I can only assume this is a seldom issue of our networking framework called uLink.

How often did you encounter this issue so far?
I hope only once.