Today I have found one bug in JoinEdge command, and another bug in BlendSrf command. The smoking gun is the attached Rhino 7 model (a.k.a. 3DM file).
rhino 7 edge bug.3dm (190.9 KB)
I tried to make (blue) blends between (magenta) rounded rectangles. There was minor problem - the rectangles had split edges.
I tried to join the split edges, but it did not work. Rhino 7 said: Command: JoinEdge… Select two unjoined edges… Select two unjoined edges… Unable to find overlapping intervals.
Next I tried to run the BlendSrf on the split edges. Sometimes it worked. Sometimes it did not work.
When it worked, Rhino 7 said: Command: BlendSrf… Select first edge… Select segment for first edge… Select next segment for first edge… Select segment for second edge…
When it did not work, Rhino 7 said: Command: BlendSrf… Select first edge… Select second edge…
By the way, I made these rounded rectangles by splitting rectangular extrusion with SubD made by MultiPipe command.