pg-mem and sequelize association error

import { Sequelize, DataTypes } from 'sequelize'; // 6.37.7, latest at time of post
import { newDb } from 'pg-mem'; // 3.0.5, latest at time of post

const db = newDb();

const sequelize = new Sequelize({
  dialect: 'postgres',
  dialectModule: db.adapters.createPg({ autoCreateForeignKeyIndices: true }),
  logging: true,
});

// Define the tables/Sequelize models
const author = sequelize.define('author', {
  // Model attributes are defined here
  authorId: { autoIncrement: true, type: DataTypes.INTEGER, allowNull: false, primaryKey: true, field: 'author_id' },
  name: { type: DataTypes.STRING, allowNull: false, field: 'name' },
}, {
  // Other model options go here
  tableName: 'author', schema: 'public', timestamps: false,
});

const textbook = sequelize.define('textbook', {
  bookId: { autoIncrement: true, type: DataTypes.INTEGER, allowNull: false, primaryKey: true, field: 'book_id' },
  title: { type: DataTypes.STRING, allowNull: false, field: 'title' },
}, {
  tableName: 'textbook', schema: 'public', timestamps: false,
});

// join/through-table definition
const textbookAuthor = sequelize.define('textbookAuthor', {
  bookId: { type: DataTypes.INTEGER, allowNull: false, primaryKey: true, field: 'book_id' },
  authorId: { type: DataTypes.INTEGER, allowNull: false, primaryKey: true, field: 'author_id' },
}, {
  tableName: 'textbook_author', schema: 'public', timestamps: false,
});

// Standard many-to-many association
author.belongsToMany(textbook, { through: textbookAuthor, foreignKey: 'authorId', otherKey: 'bookId' });
textbook.belongsToMany(author, { through: textbookAuthor, otherKey: 'authorId', foreignKey: 'bookId' });

// Alternate many-to-many association, using 2 one-to-many associations instead
author.hasMany(textbookAuthor, { foreignKey: 'authorId' });
textbookAuthor.belongsTo(author, { foreignKey: 'authorId' });
textbook.hasMany(textbookAuthor, { foreignKey: 'bookId' });
textbookAuthor.belongsTo(textbook, { foreignKey: 'bookId' });

await sequelize.sync();

// Insert the test data
db.public.none('INSERT INTO "public"."author"("name") VALUES (\'John Doe\'), (\'Einstien\'), (\'Steve\'), (\'Bill\'), (\'Bob\');');
db.public.none('INSERT INTO "public"."textbook"("title") VALUES (\'World History\'), (\'Literature 101\'), (\'Math 101\'), (\'Science 101\');');
db.public.none('INSERT INTO "public"."textbook_author"("author_id", "book_id") VALUES (1,1),(2,1);');
console.log(db.public.many('SELECT * FROM public."textbook_author"'));

// This one works with pg-mem, & requires the "2 one-to-many" pattern
// Sequelize doc: https://sequelize.org/docs/v6/advanced-association-concepts/advanced-many-to-many/#using-one-to-many-relationships-instead
const resTest = await textbook.findOne({
  where: { bookId: 1 },
  include: {
    model: textbookAuthor,
    // right: true, // works as expected
    // required: true, // works as expected
    include: {
        model: author,
        // right: true, // works as expected
        // required: true, // usually works. ONLY errors if the "textbookAuthor" is "required: false"
    },
  },
});
console.dir(resTest.dataValues, { depth: 3 });

try {
  // this one just needs the "belongsToMany" pattern
  // does NOT work with pg-mem, but works in actual databases
  // Squelize doc: https://sequelize.org/docs/v6/core-concepts/assocs/#implementation-2
  const resTest = await textbook
  .findOne({
    where: { bookId: 1 },
    include: {
      model: author,
      // These options alter the SQL questy, but seem to have no affect on if it works
      // right: true,
      // required: true,
    },
  });
  console.dir(resTest.dataValues, { depth: 3 });
} catch (e) {
  console.log(e);
}
process.exit();