Triangulation problem

Hi,

I'm having trouble triangulating a shape, the shape is displayed correctly in DRAW but not in my software, see the screenshots.

I use BRepMesh_IncrementalMesh for triangulation and I tried different linear deflection parameter.

The shape is the result of a diff between two faces and seems to be invalid, but I have not been able to fix it with fixshape, result of checkshape:

On Shape faulty_1 :
BRepCheck_InvalidImbricationOfWires

Faulty shapes in variables faulty_1 to faulty_1 

Other shapes are usually triangulated correctly in my software.

Is DRAW using something else for triangulation? Is there a way to fix my shape?

Best regards.