NWMax Plus does not perform ResetXForm on meshes with the skin modifier. It tends to screw up the weights.
Try this:
Select your skinned mesh
In the right-side nav panel select the "Hierarchy" tab, with "Pivot" selected in the middle of the panel you will see the "Adjust Transform" rollout, in the "Reset" group select "Scale".
This should solve the scale that is not 1 issue.
Try exporting your model again.
MDA