View attachment 326791
If that is the case then explain how the Ottomans 80k stack just walked from point A to point B through my fort in Trebizond (and another 10k is in the process of doing the same thing). Because I can guarantee you that there is no way a human player would be able to just blatantly ignore that fort and walk on by while the garrison cheers them on and wishes them a happy journey.
And while we're on the topic of "any special exemptions" for the AI, it seems to me (and please do correct me if I'm wrong because I'm trying to figure out how this insanity works) that if the player takes an enemy AI keep that this keep then doesn't project any ZoC to block the enemy. Whereas if the AI takes one of the players keeps it does project a ZoC.
It's almost as if, and I'll give Pdx the benefit of the doubt and say that this is not the case, this whole thing with forts and ZoC was designed to confuse and annoy the players with rules that half the time dont even seem to make sense and with outcomes that are too hard to predict.
Edit: Infact the state that the "fort system" is in at the moment breaks any sense of immersion and instead of being a tool to be used it feels more like an annoyance that you have to learn to play around.
And no... making the upkeep cheaper or making them give you Army Tradition isn't going to fix the underlying issues with the system.
As Makaramus said, the above works for a player as well as the AI. It's just that players tend not to even try to make a move like this, because it isn't intuitive - we see the fort, assume we can't move through it, and so never tell the army to try to move to point B. The AI doesn't have that problem, because it knows every path available to it.
And no, Paradox are not just doing this to confuse players. It's just a difficult problem. They tried replacing it with a much simpler system a few patches back, but it caused more problems than it solved.