Well maybe it's how it's supposed to work, i dont know, i havent been following the game
for long. Thing is, i just finished a game with 3 AIs in a 5 stars map.
When the game finished (i had to surrender... i was sandwiched by 2 of em, had a battle
going for about 30 mins, i shouldnt have sent reinforcements in, lost most of my fleet lol)
i was checking the stats they give you at the end, when i noticed that the AIs didnt kill 1 single pirate, their stats were flat. So either the stats are broken, or putting bounties on the AIs only get you free of the raid, but pirates wont attack em. I dont know if this always happen, i'll check the stats again after my next game.