How come some buildings ( Magical chess set, Moonstone library set) are making floating movements? Does that mean , they are not connected in the right way?
No they're fine. That's just what they decided to do with them graphically, for some reason. There are a few 'floaty' buildings in the early game, I remember, such as The Floating Citadel and The Hallowed Shrine.
I'm flashing back on the chess set, thanks for that. You do not want to park any of your dark signposts over next to the thing, you have the darnedest time digging them out again.