Different versions of the same map are treated as different maps. So every time developers even slightly change something in the map, you have a chance of getting this popup. Today they fixed some issues in both Arena maps
I'm having some trouble with the .nasset file format some of the maps are in, e.g. halls alt, gatehouse. It looks like blender doesn't support it. I couldn't find a converter that supported it either, and renaming to a .glb file didn't work either.
