From what I've gathered, it isn't just affecting EC. It is also happening to one of the Armas, Rust, and Ark...probably others too. So its a Steam thing, not a BE thing.
I've been struck with the same blight, though I have been playing a couple of hours earlier and had no issues until now
theyre going to have to either extend the campaign run time .... or possible even restart the whole damn thing if this keeps up, losing the weekend playtime for a lot of players
Happened to me too couple of days ago, fixed by executing STEAM with administrator rights. it normaly has administrator rights but you have to do it on puropse, try it.