Not sure if this is a bug but my generated default map and vanilla continents map settings are identical though both have a very island-y design. The Archipelago map is just a very scaled down unusable version of the other two as there is zero space to build and there are no ores due to the island being so small.
I would of thought the vanilla continents map style to be like big landmasses like vanilla and the archipelago map to be islands.
Though could be a mod conflict?
