Some of the stuff in the tech tree is wrong, like some buildings not requiring the castle level they are at. The cathedral has me bugged, though. I'm not sure why I can only build it at 1 province. I know that some stuff like the chancellory can only be built once but I don't think that is the case with a cathedral.

I have around 3 provinces with both a church and a citadel but only 1 can build the cathedral. Coincidentally or perhaps not, it is also my capital, the one with the chencellory and admiralty.

Also, monastery doesn't seem to require a chapter house or maybe just a chapter house anywhere because I can build both in some provinces just after church.