I believe the edge is joined, and needs to be detached. I tried UnjoinEdge command, which doesn’t seem to do anything. Is there something I am missing?
If it helps, the UnjoinEdge command does work in the background. For example, when i use UnrollSrf on both these versions, I get different outputs (as they should work). But, when I use the Gumball to manipulate, they seem to be joined at the Vertex.
I tried Rotate3D as well as Gumball manipulations, but It does seem to be joined. Maybe something is wrong with my polysurface itself? Could you take a look at the attached file, does your method work on that file?