Farms are enabled on Standard difficulty.
Since Yellow stays allied to you on this difficulty, Green also stays allied to you on this difficulty (the trigger for Green to enemy you is after you eliminate one of Yellow’s three Kings).
I can see why this is a problem. I think a dev fix for this would be to have Yellow unally you at some point on Standard difficulty. I guess it could be pretty late into the game or after Teal is eliminated. At the moment you just kill Teal and sit around with two allies.
How to reproduce OP’s problem:
- Play Ivaylo 1 on Standard difficulty
- Defeat Teal and stay allied with Yellow and Green
Looks like you can also enemy Green and nothing will happen on Standard difficulty if you stay allied with Yellow:
But setting Yellow to enemy makes Green change stance to enemy you, although the blockers to Green’s base don’t disappear if you do this: