Champion the culture causes game over?

[Troubles The Cat]

Is this a known bug or something from a mod? I can't imagine which mods would do it as I only have some QOL ones and magic, but can't find anything when googling. I fuffiled all the requirements to champion the culture of Meath in ireland won the war and then it said game over you have no lands

[Troubles The Cat]

Oh I wonder if it's because meath is owned by ireland who you go to war with, but the land IN meath is owned by scottland?