Some fan-fiction:
By the uneven light of ten thousand burning AI wrecks littering the battlefield, a lone engineer can be seen. It wields a tiny paintbrush: in the battle that butchered the pride of the AI fleet the intolerable happened: some of the Haagenti turrets were scratched, even worse: one was lightly dented. A second engineer slowly hovers into view: some of the flower arrangements that decorate the Haagenti forcefields have gone askew.
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In other words: I think that in these fortress cases, the AI should lose some of its emergent intelligence, designate a very large set of ships, move all ships to the same point for 10 minutes or so, and then group move towards the enemy home station.
And the size of this group should double if the previous group was not successful.
EDIT: Oops, I see you already see the problem.
2nd EDIT: And the squish is gone. Thanks.