Materials swap places after reimporting Luxology Modo's *.lxo file

I have a several objects in my game which I've created using Luxology Modo tool. Some of those objects have several materials assigned. Each time I use Luxology to make a change to the mesh, that is when I save the file and when the model is reimported to Unity, materials or rather it's order end up being all messed up (they swap places). Any thoughts how to prevent this situation from happening?