mongoose set nested bug?

bob.spec.coffee

mongoose = require 'mongoose'

schema = new mongoose.Schema
  nested:
    thing: String

Bob = mongoose.model('Bob', schema)

describe 'Bob', ->
  bob = null

  beforeEach ->
    bob = new Bob(nested: {thing: 'widget'})
    expect(bob.nested.thing).toEqual 'widget'

  it 'set null', ->
    bob.set(nested: null)
    expect(bob.get('nested.thing')).toBeUndefined()

  it 'set undefined', ->
    bob.set(nested: undefined)
    expect(bob.get('nested.thing')).toBeUndefined()

  it 'set empty object', ->
    bob.set(nested: {})
    expect(bob.get('nested.thing')).toBeUndefined()

  it 'virtual property null', ->
    bob.nested = null
    expect(bob.get('nested.thing')).toBeUndefined()

  it 'virtual property undefined', ->
    bob.nested = undefined
    expect(bob.get('nested.thing')).toBeUndefined()

  it 'virtual property empty object', ->
    bob.nested = {}
    expect(bob.get('nested.thing')).toBeUndefined()

run with jasmine-node --coffee bob.spec.coffee