Offset surface problem

Making an “srf offset” for this type of polysurface gives some problems. It could be a limit of Rhino (Rhino 6.11), a bug to solve, or a user error, I do not know…
offset srf problem.3dm (1.5 MB)

Hello - I see that, thanks.
https://mcneel.myjetbrains.com/youtrack/issue/RH-50280
-Pascal