Weird clipping behaviour with grid-like Voronoi diagram

[OneEyeMaker]

I'm trying to build Voronoi diagram from grid-like set of points.

I've two such sets of sites: for first one this implementation works perfectly, but for second one it panics at runtime with message Edge crosses box, intersection must exist. The problem is that sites of these sets differ only by few (floating point) epsilons. And there are no sites outside bounding box.

Links:

• first set of sites.
• second set of sites.

Code that I use to create Voronoi diagram:

VoronoiBuilder::default()
        .set_bounding_box(BoundingBox::new(Point {x: 800.0, y: 800.0}, 1600.0, 1600.0))
        .set_sites(points)
        .set_clip_behavior(ClipBehavior::Clip)
        .build()
        .unwrap();

What causes such weird behavior with clipping enabled (for almost identical sets of points)?