Odd Behavior Split (Bug?)

In the attached file I have a polysrf and a closed curve (purple).

I did a split of the polysrf using the closed curve (i was thinking they would be about the same so might as well try it). My expectation was that either the split would fail or I would get two pieces. Instead I get 5 pieces.

It’s almost like an explode command.

It looked odd to me so I thought I would share.

Problem Split 1.3dm (2.8 MB)

something is wrong with the curve, if you intersect it with the object it does not cut through so it deviates did you change it after creating? if you use a cut plane instead it will split it successfully into 2 pieces.

Does seem odd - how was the curve made? Something in the curve-surface intersector is making it separate the surfaces.

If I create a cut plane in the same plane as your split curve and split the object with that or the intersection curve of the plane and the object, I get left with only two objects.

ProblemSplit1_Test2.3dm (176.5 KB)

I created the curve using Polyline.

Keep in mind I was not trying to accomplish anything in particular here. I had that older curve sitting around and on a lark tried a split. The result was so bizarre that I posted it as possibly indicative of a bug somewhere.