missing collisions for some rotations of a GImpact shape

This issue affects both jme3-bullet and jme3-jbullet. It was reported at the Forum: https://hub.jmonkeyengine.org/t/possible-bug-in-physics/41977

Here is the test code:

import com.jme3.app.SimpleApplication;
import com.jme3.bullet.BulletAppState;
import com.jme3.bullet.collision.PhysicsCollisionEvent;
import com.jme3.bullet.collision.PhysicsCollisionListener;
import com.jme3.bullet.control.RigidBodyControl;
import com.jme3.light.DirectionalLight;
import com.jme3.material.Material;
import com.jme3.math.ColorRGBA;
import com.jme3.math.Quaternion;
import com.jme3.math.Vector3f;
import com.jme3.scene.Geometry;
import com.jme3.scene.Mesh;
import com.jme3.scene.Node;
import com.jme3.scene.Spatial;
import com.jme3.scene.VertexBuffer;
import com.jme3.scene.shape.Box;

import static java.lang.Math.PI;

public class Bug2 extends SimpleApplication implements PhysicsCollisionListener {
  private int ticks = 0;
  private int lastCollisionTick = 0;
  private Mesh boxMesh;
  private Material mat;
  private BulletAppState bulletAppState;
  private Node box2;

  public static void main(String[] args) {
    Bug2 bug = new Bug2();
    bug.showSettings = false;
    bug.start();
  }

  @Override
  public void simpleInitApp() {
    bulletAppState = new BulletAppState();
    this.stateManager.attach(bulletAppState);
    bulletAppState.getPhysicsSpace().addCollisionListener(this);

    viewPort.setBackgroundColor(ColorRGBA.Gray);
    viewPort.getCamera().setLocation(new Vector3f(0,0,-10000));
    viewPort.getCamera().lookAt(Vector3f.ZERO, Vector3f.UNIT_Y);
    viewPort.getCamera().setFrustumFar(20000);
    /*
     Here the original code builds the cube from coordinates.
     The issue does not happen with JMonkey's Box at least for these particular values.
     */
    boxMesh = new Mesh();
    Box q = new Box(2000,2000,2000);
    for(VertexBuffer origin : q.getBufferList()) {
      boxMesh.setBuffer(origin.getBufferType(), origin.getNumComponents(), origin.getFormat(), origin.getData());
    }
    boxMesh.updateBound();

    mat = new Material(assetManager, "Common/MatDefs/Light/Lighting.j3md");
    mat.setColor("Diffuse", ColorRGBA.Blue);
    final DirectionalLight light = new DirectionalLight();
    light.setDirection(new Vector3f(0.5f, -0.7f, 1.0f));
    rootNode.addLight(light);

    createBoxGivenRotation(new Quaternion());
    box2 = createBoxGivenRotation(randomQuaternion());

  }

  private Node createBoxGivenRotation(Quaternion q) {
    Geometry spatial = new Geometry("Box", boxMesh);
    RigidBodyControl control = new RigidBodyControl(1.0f);
    spatial.setMaterial(mat);
    spatial.addControl(control);
    control.setKinematic(true);
    Node node = new Node();
    node.attachChild(spatial);
    rootNode.attachChild(node);
    bulletAppState.getPhysicsSpace().add(control);

    node.setLocalRotation(q);
    node.setLocalTranslation(Vector3f.ZERO);

    return node;
  }

  private static Quaternion randomQuaternion() {
    return new Quaternion().fromAngles(randomAngle(), randomAngle(), randomAngle());
  }

  private static float randomAngle() {
    return (float)(Math.random() * 2 * PI);
  }

  @Override
  public void simpleUpdate(float tpf) {
    super.simpleUpdate(tpf);
    /* If no collision is detected we abort (collisions are detected in 1 tick, 200 is an overkill) */
    if(ticks - lastCollisionTick > 200){
      System.out.println("Bug in physics! You can replace the random quaternion for the one printed on the previous line.");
      System.exit(0);
    }
    ticks++;
  }

  /* If a collision is detected, remove the second cube and try again with another random rotation. */
  @Override
  public void collision(PhysicsCollisionEvent event) {
    Quaternion q = randomQuaternion();
    int ticksSinceLastCollision = ticks - lastCollisionTick;
    System.out.println("Collision event in " + ticksSinceLastCollision + " ticks : retry with rotation quat " + q);
    lastCollisionTick = ticks;
    destroyBox(box2);
    box2 = createBoxGivenRotation(q);
  }

  private void destroyBox(Node box) {
    Spatial spatial = box.getChildren().get(0);
    RigidBodyControl control = (RigidBodyControl) spatial.getControl(0);
    control.getPhysicsSpace().removeCollisionObject(control);
    box.getChildren().get(0).removeFromParent();
  }
}

Start by running the Bug2 reproduction entry point from the issue and compare collision behavior for the two implementations named: jme3-bullet and jme3-jbullet. Trace the RigidBodyControl and PhysicsCollisionListener paths for GImpact shapes under varying rotations. Done means collisions are consistently detected for the reproduced rotations in both implementations.