CoreMongooseArray(0) bug instead of Normal array

This is my index.js file

const mongoose = require('mongoose');

const Dishes = require('./models/dishes');

const url = 'mongodb://localhost:27017/conFusion';
const connect = mongoose.connect(url);

connect.then((db) => {

console.log('Connected correctly to server');

Dishes.create({
    name: 'Uthappizza',
    description: 'test'
})
.then((dish) => {
    console.log(dish);

    return Dishes.findByIdAndUpdate(dish._id, {
        $set: { description: 'Updated test'}
    },{ 
        new: true 
    })
    .exec();
})
.then((dish) => {
    console.log(dish);

    dish.comments.push({
        rating: 5,
        comment: 'I'm getting a sinking feeling!',
        author: 'Leonardo di Carpaccio'
    });

    return dish.save();
})
.then((dish) => {
    console.log(dish);

    return Dishes.remove({});
})
.then(() => {
    return mongoose.connection.close();
})
.catch((err) => {
    console.log(err);
});

});

this is my dishes.js file:

    const mongoose = require('mongoose');
const Schema = mongoose.Schema;

var commentSchema = new Schema({
    rating:  {
        type: Number,
        min: 1,
        max: 5,
        required: true
    },
    comment:  {
        type: String,
        required: true
    },
    author:  {
        type: String,
        required: true
    }
}, {
    timestamps: true
});


var dishSchema = new Schema({
    name: {
        type: String,
        required: true,
        unique: true
    },
    description: {
        type: String,
        required: true
    },
    comments:[commentSchema]
}, {
    timestamps: true
});

var Dishes = mongoose.model('Dish', dishSchema);
module.exports = Dishes;

I am getting an error that says:

isNew: false,
  errors: undefined,
  _doc: {
    _id: 6207ff6455a72312f4426861,
    name: 'Uthappizza',
    description: 'Updated test',
    comments: CoreMongooseArray(0) [
      _path: 'comments',
      toBSON: [Function: toBSON],
      _atomics: {},
      _parent: [Circular *1],
      _cast: [Function: _cast],
      _markModified: [Function: _markModified],
      _registerAtomic: [Function: _registerAtomic],
      '$__getAtomics': [Function: $__getAtomics],
      hasAtomics: [Function: hasAtomics],
      _mapCast: [Function: _mapCast],
      push: [Function: push],
      nonAtomicPush: [Function: nonAtomicPush],
      '$pop': [Function: $pop],
      pop: [Function: pop],
      '$shift': [Function: $shift],
      shift: [Function: shift],
      pull: [Function: pull],
      splice: [Function: splice],
      unshift: [Function: unshift],
      sort: [Function: sort],
      addToSet: [Function: addToSet],
      set: [Function: set],
      toObject: [Function: toObject],
      inspect: [Function: inspect],
      indexOf: [Function: indexOf],
      remove: [Function: pull],
      id: [Function: id],
      create: [Function: create],
      notify: [Function: notify],
      isMongooseDocumentArray: true,
      validators: [],
      _schema: [DocumentArray],
      _handlers: [Object]
    ],
    createdAt: 2022-02-12T18:41:40.049Z,
    updatedAt: 2022-02-12T18:41:40.096Z,
    __v: 0
  }

the issue is in the output of the comments part, can someone pls help me?
I have tried reading about it online, but i am not able to get anything where is the problem?

Ps: this is a part of course, I have followed all the steps very carefully, but I am still getting the problem