The AI doesn't cheat, except for that one thing: it knows which provinces you control, and when it declares war on your nation and has access to spells like Call of the Wild or Fires from Afar, it will liberally (yet randomly) cast it on one of your provinces. Everyone I know thinks that feature is OK, as the AI isn't smart enough to do proper scouting.
Your Enchantress was just unlucky to be in the wrong place at the wrong time. Give her a ring of fire resistance in your next game
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