Incorrect results of model.combine

[PechenTreski]

Hello,
I came across a problem with a strange behaviour of model.combine. I have a circle and a polygon made of lines, and when I try to subtract the polygon from a circle, then a couple of lines stay visible outside of the result shape.

var circle = { 
  type: 'circle', 
  origin: [-122, -154],
  radius: 402.7,
  units: 'cm'
 };

var modelCircle = { paths: { myCircle: circle } };

var line1 = { 
  type: 'line', 
  origin: [-500, -399], 
  end: [-499, 201] 
 };
 var line2 = { 
  type: 'line', 
  origin: [-499, 201] ,
  end: [-670, -136]
 };
 var line3 = { 
  type: 'line', 
  origin: [-670, -136] ,
  end: [-500, -399] 
 };

var modelLinien = { paths: { myLine1: line1, myLine2: line2, myLine3: line3 } };

rootModel = m.model.combineSubtraction(modelCircle, modelLinien);

// same result
rootModel2 = m.model.combine(
            modelCircle,
            modelLinien,
            false,
            true,
            true,
            false
        );
		
var svg = m.exporter.toSVG(rootModel);
document.write(svg);

[PechenTreski]

I need to add that it only happens when the rightmost (in my case) line of the polygon is strictly vertical :)