A MCUT HALFEDGE MESH ERROR occurred in a special place.

[BinalyseZXC]

When I use a spiral surface and a rotating surface (which have been merged) to cut a cylinder, a MCUT HALFEDGE MESH ERROR occurs.I speculate that the point where the error occurred is located at the red circle in the image. Because if the endface of the cylinder does not exceed this point, the error will not occur.

Strangely, if use the cylinder to cut the merged surface, I can obtain the correct results and errors will not occur.

[chitalu]

what is your debug output?