Firstly, I couldn't believe... then... I was very surprised, and now I'm confused.
I mensioned that AI players make deals with enthusiasm only with HUMANs. And if to enter saved game as AI player, momently AI players offer different deals, if our relationships allow. And I've never (!!!!!!!!) observed any AI player's allies and even trade pacts. So, has anyone collided such AI behave model? 
And what's fun of such situation with AI players if it's common? 
PS: The only thing I really appreciated in 'Diplomacy' expansion is Pirate missions.