Through association preloading doesn't work

bug_report.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  gem "rails", '~> 6.0.0'
  gem "sqlite3"
end

require "active_record"
require "minitest/autorun"
require "logger"

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
ActiveRecord::Schema.define do
  create_table :users, force: true
  create_table :accounts, force: true do |t|
    t.integer :is_not_deleted, default: true
  end

  create_table :memberships, force: true do |t|
    t.integer :user_id
    t.integer :account_id
  end
end

class ApplicationRecord < ActiveRecord::Base
  self.abstract_class = true
end

class User < ApplicationRecord
  has_many :memberships, inverse_of: :user
  has_many :accounts, through: :memberships

  def primary_email
    memberships.first.account
  end
end

class Account < ApplicationRecord
  has_many :memberships, inverse_of: :account
  has_many :users, through: :memberships

  default_scope { where(is_not_deleted: true) } # Comment this line to make the test pass
end

class Membership < ApplicationRecord
  belongs_to :user, inverse_of: :memberships
  belongs_to :account, inverse_of: :memberships
end

class BugTest < Minitest::Test
  def test_association_stuff
    account = Account.create!
    user = User.create!
    user.accounts << account

    q_count = count_sql_queries do
      users = User.preload(:accounts)
      users.first.primary_email
    end
    assert_equal 3, q_count
  end

  def count_sql_queries(&block)
    count = 0
    counter_f = ->(_, _, _, _, payload) {
      unless (%w[CACHE SCHEMA]).include?(payload[:name])
        puts payload[:sql]
        count += 1
      end
    }
    ActiveSupport::Notifications.subscribed(counter_f, "sql.active_record", &block)
    count
  end
end