TUG is both good news and bad news. The good news is that the game is getting ready to roll out a major update that will include a lot of fun stuff for players. Like what, you ask? Like hunting, and farming and all the goats you can ask for. Even if you ask for a lot of goats, you can have never have enough goats.
So what's the bad news? Well, it turns out that the team kind of broke Proving Grounds on the way to adding in new features. Rather than delaying the update, the current stopgap solution is to block off Proving Grounds and simply add it back in during a later update. You can read the full update if you need some specifics; the hope is that players won't ultimately be surprised when the update goes live for everyone.