Execute breaks closed shapes

[antonbrams]

i'm using two functions to cut close or open shapes

// this one opens curve all the time, so i have to close it manually
const boolean_area = (type, path_a, path_b) => {
       // to make sure that the path is closed (just copying the first point and appending at the end)
	close_paths(path_a)
	close_paths(path_b)
	const {Clipper, PolyType, Paths, ClipType} = clipper_lib
	const result = new Paths()
	const params = Clipper.ioPreserveCollinear | Clipper.ioStrictlySimple
	const clipper = new Clipper(params)
	clipper.AddPaths(path_a, PolyType.ptSubject, true)
	clipper.AddPaths(path_b, PolyType.ptClip, true)
	clipper.Execute(ClipType[type], result)
	close_paths(result)
	return result
}

// this one breaks the subject curve at random places and i can't fix it easily
const boolean_line = (type, subject, clip) => {
	const {JS, Clipper, ClipType, PolyTree, PolyType} = clipper_lib
	const cleaned = JS.Lighten(subject, 0.01 * scale)
	const result = new PolyTree()
	const params = Clipper.ioPreserveCollinear | Clipper.ioStrictlySimple
	const clipper = new Clipper(params)
	clipper.AddPaths(cleaned, PolyType.ptSubject, false)
	clipper.AddPaths(clip, PolyType.ptClip, true)
	clipper.Execute(ClipType[type], result)
	return Clipper.PolyTreeToPaths(result)
}

// this breaks the line at random locations too
const b = Clipper.SimplifyPolygons(a, PolyFillType.pftEvenOdd)

i'm using scale factor 4 and they both producing open paths at some random locations "clipper-lib": "^6.4.2",

[antonbrams]

Hello? Anybody alive here?