What is going on

Can you guys tell me what is happening with the blue surface. After splitting with black solids it’s meshes go haywire like on attached image. Geometry was originally created in WIP.

WhatIsGoingOn.3dm (272.9 KB)

Upon further investigation I found out the immediate reason for the split problem.
All black solids were extruded from planar closed curves. And those curves were made by first Rectangle command and than Fillet Corners.
But look at the control points…
As I said original geometry was done in WIP. I’ve never experienced anything like this ever before and can’t recreate it again. It might be one of those one in a million things…

WhatIsGoingOn1.3dm (201.3 KB)

the blocks left and right are responsible for it because they have overlapping surfaces. the middle one seems ok. taking the profile from the flat end and splitting those micro parts off then extruding it again did the trick. if you still need it or not. if thats a problem with the wip i cant say somebody shall have a look thats why i put it into serengeti.

Thanks Richard,

I should have been less hot headed and do some more of my own investigation before posting it to the forum.