I won't say its a bug, but something which should be polished in AI strategy. I am playing the Valley of Tezkal 2nd challange, where is a single Victory Square. I ended up in one turn, where Gary missed only 1 star to win and a crocodile (5hp) occupying the Victory Square. Unfortunately I had nothing to kill it, so as a desperate move I made that square Lava. Instead of keeping the Crocodile there and winning the game AI flew away from the Victory Square. My impression is that AI playing the same strategy during the whole gameplay instead of changing it if it is close to win. (4 turns later I won.)
Gary is more of a roleplayer than a strategist, he likes to get into the minds of the monsters and really bring them to life. To Gary, winning the battle is far less important than evoking the essence of his characters. And Coatldiles, essentially, hate lava.