Physics collision listener contains list of "null" after reloading scene

Troubleshooting physics
1

Dear community,

I try to implement save/load functionality, and come to two errors:

  1. Fired bullets appear lose userObject in collisionlistener
  2. CameraNode stops working.

1.First error: I have this code triggered from ActionListener:

  public void load() {
    String homeDirectory = System.getProperty("user.home");
    String fileName = "\\Saves\\" + "QSave.j3o";
    assetManager.registerLocator(homeDirectory, FileLocator.class);
    Node loadedNode = (Node) assetManager.loadModel(fileName);
    physicsSpace.removeAll(rootNode);
    rootNode.detachAllChildren();
    List<Spatial> RootChildren = loadedNode.getChildren();
    for (Spatial child : RootChildren) {
      rootNode.attachChild(child);
      physicsSpace.addAll(child);
    }
  }

If I save the game at the moment when character have fired some bullets and reload scene (without exiting game) , then once bullet touches the destroyable object, no collision is registered.

The CollisionListener class in the event “collision” has event.getNodeA() and event.getNodeB() as null.

I see the attribute “nodeA” exists (event.nodeA is not null, but the method getNodeA/B is using internally “getUserObject” and userObject is empty.

Am I doing physics update in incorrect moment?
Which method should be used for that?
I use sequential threading for physics, just in case it can matter

2.Camera - here I do not get the reason at all.
In the AnalogListener I see cameraNode is extracted, new position/rotation is applied, but somehow on the screen camera is not changed.

Please help if you know something, I spent this whole day debugging on it :persevere::disappointed_relieved: