This has never happened to me before, but I have a model with which becomes destroyed when I increase its scale in Unity3D after import.
BANG! That’s a woman, believe it or not.
I’ve tried both applying Loc,Rot,Scale and clearing it, but that doesn’t work. I’ve read it is something to do with mismatched scaling of bones or something totally random like that.
My guess goes to not applied scale before exporting. But that would be wild guessing at the moment. Why not provide the blend file and a unity package instead?
I’m afraid I can’t as this is going to production. I tried applying the scale before export on both the Mesh and Armature individually and both together. Seems to make no difference.
I also tried using the scaler in the fbx exporter instead but this takes the model 100 miles from its origin, which is most inconvenient.