Bad parents in the notifications when sub-objects are replaced

[bago]

var subModel = {
  c: ko.observable(1),
  d: ko.observable(0)
};

var subModelB = {
  e: ko.observable(0),
  f: ko.observable(1)
};

var model = {
  a: ko.observable(1),
  b: {
    g: ko.observable(0),
    h: ko.observable(0),
  },
  sub: ko.observable(subModel),
};

var w = ko.watch(model, { depth: -1, oldValues: 1, mutable: true, tagFields: true }, listener);

model.sub().c(4); // this is notified correctly

model.sub(subModelB);
model.sub().e(4); // this is notified with the wrong number of parents

Once you replace an observable object the new notifications have one more "parent" that is not expected.