Hi Armin, thanks for posting this bug along with the 3DM file so I could reproduce it over here.

It definitely seems to be a bug in the curve offset function in the geometry library.

The bug seems to be triggered when doing a trimmed offset, when the trimmed fragment is over a certain minimize size cutoff point, but also less than a certain fractional size relative to the offset distance.

Those different areas that you notice when it kicks in are areas where the pieces happen to fit within that particular range.

I think I can fix it, but I think it is safest not to try until v3 because just tightening up the distances could result in additional segments being deleted as well as those little pieces. So I'll have to be careful about the fix and it's better for it to get some beta testing.

In the meantime, those little pieces are just excess bits, you can just delete them to get rid of them.

- Michael