Based on my experience, the reproducibility of AI moves on identical or similar game versions should be very good. Therefore, to better understand what versions of the game you have, how the AI behaves on your computers, but with my save from the end of the third day? And please upload your corresponding saves so we can see where the AI will go from them, but already on my platinum difficulty.
During my first playthrough, I artificially placed my hero one, two, or three squares closer to his castle - it didn't work!