Hi,
I have the same issue (all DLC downloaded and enabled). I used the mod manager or the vanilla mod manager from activision. Disabled all mods except faction unlocker, the community bug fix and the UI modding framework.
I changed the "Brass keep" to NO and tried different settings for the brettonian kingdom. Then did a reset of the framework. But there is always a script error. I can't close the window.

I disabled the UI modding framework and started a campaign with ulfrik. It worked for several turns. I embarked in a ship and went to explorer a "treasure chest" in the sea. When I activated the chest and wanted to enter the battle. I had a black screen, I suppose the game stalled because I had to log off windows.
I tried several other minor norsca factions. It seems they are working (no script errors). I didn't try (yet) to loot a treasure chest in sea to see the behaviour with undead pirates.
could it be that ulfrik or wintertooth have a conflict with the new factions in north empire?
If there is any way I could retrieve the lua script error message, please tell me I will paste it here.

i have the same issue