So playing another custom map game as a kind of fully grown Netherlands but not the Netherlands. A neighbour annexed Luxemburg early on in the game but it suddenly broke free soon after. On the pop up I clicked the nations shield to see if I could quickly vassalise them and something was slightly off about it.
Its religion isn't the only thing slightly off. Because the rebels had gained their independence and their capital was in North Africa! So suddenly there is a westernised sunni nation in Africa at the start of the game!
But that wasn't the only weird thing.
Luxemburg still owned Luxemburg. So quite quickly I invaded. Tunis also invaded their North African holdings at the same time. Also during the occupation, the province decided it would much rather be with me, as I was Germanic and Catholic not Berber and Sunni, so I gained a free core on Luxemburg
Not for the first time a country gained independence in a custom game using random nations (not using France etc but province name and random attributes) and appearing in the wrong place. In my previous custom game, Kai, a Japanese Daimyo broke free and appeared in Croatia. (Posted this before but since I brought it up)