Money Script (?) producing infinite stacks in small nations

So, in my Numidia game, which went on for 400 turns, I had a good relationship with Carthage. Eventually I bought their African colonies, and after some Roman conquest, they were left with just Carthage and the Baleares. Nestled inside me, Numidia, they had military access. All their ships were destroyed. Essentially, over time, they produced 8-9 full stacks, which just sat around in Carthage because their AI couldn't figure out how to do foreign military operations from the position they were in, and seemed to prioritise building armies over building boats.

I suspect this has something minor to do with the strait at Tangiers, I was reading that it caused the AI to vacillate intensely on its pathing decisions sometimes.
I'll upload the save, if anyone's interested. It was an utterly fantastic game I had with Numidia, by the way, first time I've gotten anywhere over ~150 turns!