I'm happy to learn the AI has access to information regarding wonder completion. It makes it that bit more competitive (If indeed this behaviour is true).
I would be disappointed if the AI was getting free production to rush a wonder before the player. But if it's being rushed through legal means, then visibility is a good thing.
This complaint falls into the "I want a better AI, not a cheating AI" category of complaints, which has less to do with the AI and more to do with the user's unreasonable expectations of modern AI in a strategy game.
That's not to say the AI in Civ has no room for improvement. It has, and I wish more focus was put into improving it, but removing these small advantages is certainly no way to do it.