Timestamps schema options not applying to "createdAt" when depth is more than 1

[JellyKid]

Weird issue here that I can't figure out if it's me or mongoose or mongo. When trying to customize the timestamp fields I can only get updatedAt to customize, while the createdAt field fails to show up... Please see below.

const schema = new mongoose.Schema(
  {
    firstName: String,
    lastName: String,
    email: String,
    initials: {type: String, default: 'AAA'},
    hash: {type: String, select: false},
    facebook: String,
    admin: {type: Boolean, default: false},
    enabled: {type: Boolean, default: false},
    meta: {
      authType: {type: String, default: 'local'},
      activated: {type: Boolean, default: false},
      invitationSent: Date,
      verificationToken: {type: String, select: false}
    }
  },
  {
    timestamps: {
      updatedAt: "meta.updatedAt",
      createdAt: "meta.createdAt"
    }
  }
);

> db.users.findOne({firstName: "test"})
{
        "_id" : ObjectId("58c01cde71a18209f40201a6"),
        "firstName" : "test",
        "lastName" : "user",
        "email" : "test@user.com",
        "meta" : {
                "activated" : false,
                "authType" : "local",
                "invitationSent" : ISODate("2017-03-08T15:01:50.618Z"),
                "verificationToken" : "6X9u8mxv00S9N8s6fXFcvlKY",
                "updatedAt" : ISODate("2017-03-08T15:01:50.618Z")
        },
        "enabled" : true,
        "admin" : false,
        "initials" : "AAA",
        "__v" : 0
}

If I set the createdAt field to something with a depth of 1, or don't try to customize the field it will set just fine.

[vkarpov15]

This is a bug in mongoose, nested timestamp paths don't currently work, but will work when 4.9.1 lands (ETA Sunday March 19)