Missing port

Arkanit#3617

I've just captured the settlement with an empty slot for a port building. When trying to build something in the empty slot it says: "U need to build a previous building". Razing and recapturing, leveling to a max level not helping.

Save file attached.

No single mod is being activated, so the modified.log is empty.

Arkanit#3617

Is it has to do something with Nakai's Defenders of the Great Plan with their unique temple building?