person.js

  this.findById(ownerId)
  // .lean()
  .select('contacts')
  .populate('contacts.person', 'id email avatar name nestedModel')
  // FIXME feels like we should be able to get nested populations instead
  // on building them inside the promise.
  // .populate('contacts.person.nestedModel')
  .exec()
  .then(function (doc) {

    NestedModel.populate(doc.contacts, {
      path: 'person.nestedModel',
      // FIXME this is still returning expired Flares.
      options: {
        sort: {updatedAt: -1},
      }
    }, function (err, contacts) {
      // The contacts are populated correctly with the proper nestedModel
      console.log(contacts);
      contacts.forEach(function (rec) {
        // This will log the person
        console.log('person', rec.person.toJSON());

        rec.person.toJSON({transform: function (doc, ret) {
          // It's the nested model instead of the person object expected.
          console.log('not the person!?', doc);
        }});
      });

    });
  }, function (err) {
    console.log(err);
  });