Does GKOctree have bugs?

Hi, I'm newbie of swift, iOS and this forum.
Although I've just already same reply in the following issue, my reply doesn't appear. So please let me ask here.

https://developer.apple.com/forums/thread/127384

---

GKOctree doesn't work at all. There seems to be many problems.
Here is reproduction code.

Code Block swift
import GameplayKit
class point: NSObject {
  var vec: simd_float3
  init(x: Float, y: Float, z: Float) {
    self.vec = simd_float3(x,y,z)
  }
}
func test () {
  let points = [
    point(x: 1, y: 1, z: 2),
    point(x: 2, y: 2, z: 1),
    point(x: 2, y: 1, z: 1)
  ]
  let min = point(x:0, y: 0, z: 0)
  let max = point(x:3, y: 3, z: 3)
  let box = GKBox(boxMin: min.vec, boxMax: max.vec)
  let tree = GKOctree<point>(boundingBox: box, minimumCellSize: 0.01)
  print("=== registering ===")
  for p in points {
    let node = tree.add(p, at: p.vec)
    print("at:", p.vec, "box:", node.box)
  }
  // All
  print("=== list in elements(at:) ===")
  for p in tree.elements(at: points[0].vec) {
    print(p.vec)
  }
  print("=== elements(in:) ===")
  for p in tree.elements(in: box) {
    print(p.vec)
  }
}

It generates these results in the following.

Code Block swift
=== registering ===
at: SIMD3<Float>(1.0, 1.0, 2.0) box: GKBox(boxMin: SIMD3<Float>(0.4921875, 0.99609375, 1.9921875), boxMax: SIMD3<Float>(0.50390625, 1.0078125, 2.0039062))
at: SIMD3<Float>(2.0, 2.0, 1.0) box: GKBox(boxMin: SIMD3<Float>(0.99609375, 1.9921875, 0.99609375), boxMax: SIMD3<Float>(1.0078125, 2.0039062, 1.0078125))
at: SIMD3<Float>(2.0, 1.0, 1.0) box: GKBox(boxMin: SIMD3<Float>(2.4960938, 0.99609375, 0.4921875), boxMax: SIMD3<Float>(2.5078125, 1.0078125, 0.50390625))
=== list in elements(at:) ===
SIMD3<Float>(1.0, 1.0, 2.0)
=== elements(in:) ===

Results report that each point which added to GKOctree are not in each GTKOctreeNode.box.
And when code specifies box to get elements, it doesn't return any elements at all.

Would there be any wrong in above code?
I think It may be bugs.

Platform: iOS 14.2, Playground