My NURBS surface can not add to Doc

I got a ON_NurbsSurface with IsValid() returning true but I can not add it to Doc. I tried to Create a Surface Object but failed because BoundingBox is a unit box and Geometry() returning nullptr. Please help me check it.
The attachement is the Dump() file from the surface. My Rhino is 6.0. (12.4 KB)



Hi @stankindraw,

How did you create surface? From code? From reading some file?

How can we repeat what you’ve created?

– Dale