The SOP Import node, has a Primitive Definition Section, within this Section are two toggle options;

• Packed USD Primitives
  
• Other Primitives
  

When toggling on Packed USD Primitives and setting it to; Overlay Transforms then setting Other Primitives to Overlay my mesh disappears ?

If I understand correctly the Packed USD Primitives: Overlay Transform, is suppose to handle USD files as un-packed primitives, meanwhile Other Primitives: Overlay, is suppose to allow one to import and modify certain attributes from SOPS into existing USD Geometry, but I don't see an option as to what attributes one wants to import ?