Non-strict schema properties are not accessible after loading document

[adamreisnz]

Do you want to request a feature or report a bug?
Bug

What is the current behavior?
Properties on a non-strict schema that are accessed directly (e.g. mySchema.prop) yield undefined even though they exist and have values.

Note that I am defining the blank schema like this intentionally, as suggested to me earlier in #10383

If the current behavior is a bug, please provide the steps to reproduce.

const mongoose = require('mongoose')
const {Schema} = mongoose
const uri = `mongodb://localhost:27017/test`
console.log(`Mongoose version: ${mongoose.version}`)

const FooSchema = new Schema({}, {
  id: false,
  _id: false,
  strict: false,
})
const BarSchema = new Schema({
  name: String,
  foo: FooSchema,
})

//Model
const Bar = mongoose.model('Bar', BarSchema)

//Test function
async function test() {

  //Connect to database
  await mongoose.connect(uri)

  //Create new item
  const bar = new Bar({
    name: 'Test',
    foo: {
      something: 'A',
      other: 2,
    },
  })

  console.log(bar.foo)
  console.log(bar.foo.something)
  console.log(bar.foo.other)

  await bar.save()
  const {_id} = bar

  //Query
  const barLoaded = await mongoose
    .model('Bar')
    .findOne({_id})
  console.log(barLoaded);
  console.log(barLoaded.foo)
  console.log(barLoaded.foo.something)
  console.log(barLoaded.foo.other)
}

test()

Result:

console.log(bar.foo) //{ something: 'A', other: 2 } ✅
console.log(bar.foo.something) //A ✅
console.log(bar.foo.other) //2 ✅

console.log(barLoaded.foo) //{ something: 'A', other: 2 } ✅
console.log(barLoaded.foo.something) //undefined ❌
console.log(barLoaded.foo.other) //undefined ❌

For some reason, the properties are not accessible/yield undefined when accessed directly.
Using toObject() first works and includes all the properties.

What is the expected behavior?
Expected:

console.log(bar.foo) //{ something: 'A', other: 2 } 
console.log(bar.foo.something) //A
console.log(bar.foo.other) //2
console.log(barLoaded.foo) //{ something: 'A', other: 2 }
console.log(barLoaded.foo.something) //A
console.log(barLoaded.foo.other) //2

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.
Node 16, Mongoose 6.0.7, MongoDB 4.2.8

[adamreisnz]

Thank you 🎉