[BUG] Always exporting Rhino create unexpected not welded UV mapping polygons island

As reported here
https://support.rizom-lab.com/support/tickets/287
and here
https://mcneel.myjetbrains.com/youtrack/issue/RH-60984

Rhino after making a proper UV mapping and exporting the mesh as FBX or OBJ, create an extra set of UV mapping meshes. I mean instead of creating a unique UV mapping mesh it divided itself into little meshes as shown in the video.

VIDEO