"...specifically, lying. Instead of outright saying what it wanted, sometimes the AI would feign interest in a worthless object, only to later concede it for something that it really wanted."
This is a basic negotiation tactic that does not have to be lying. Example: I've negotiated salary before, sometimes I get the "I'm sorry we would like to pay you more but it isn't in our budget." At that point I ask for more paid days off instead--and sometimes that works out very well. Was I lying when I asked for more money? Of course not. Do I want more paid days off? Yes!
Getting information from the one side and using it to your advantage is very common. When negotiating you need reasons to support your demands or else they will fall apart. This is nothing new, but a machine participating is very amusing!