I don't know this for sure, but after several games against the AI now I have the sense that it's suffering from one problem: It seems to be overactive...
I know that one of the things that I try to do for my side is to gain and foster entrenchments. Move offensively, fight battles defensively. It works.
The AI though tends to move entire stacks, leaving nothing in strategic reserve, and therefore giving up any entrenchment advantages that it might gain. I can regularly take advantage of it by using pairs of Corp, one smaller one in defense and one to move to an opening. Works every time, as long as I'm patient about my goals.