Hey, lately i'v been using pre-displaced meshes to preview my tileables because i find the displacement in Marmoset to cause a lot of stretching and artifacts. The thing i'v found is using mesh tangent space for xNormal (which is what i bake in) causes very weird and soft looking shadows/occlusion, while setting it to 3ds…
This does seem strange. One thing to note when using the 3DS Max tangent space, the green channel of the normal map is automatically inverted, which may be the reason you're seeing a difference here.