Texture content authored for the metalness workflow is converted to the specular workflow (albedo, reflectivity/specular and gloss) on export. This allows us to use a standardized shading model and know how many textures will be in use, which is important for mobile performance. The conversion process is lossless; however, your albedo, metalness and or roughness maps may look different in the layers view.
More about the differences between the metalness and specular workflows can be found here.