This problem occurred when I imported 50 fbx houses and the engine did some kind of texture override and all houses have the same texture. Probably this is because the textures have the same name.
Now i have to create 50 folders with the fbx/asset name, and import them one by one in each folder. This way i have all materials and textures separate for each house.
What would be really useful is an “create folder” option (with the fbx name) o when importing fbx, to make sure all of them have the correct textures/materials,