Factory with explicitly specified `parent` has broken associations

[Alex Kuhn]

Description

When we explicitly assign the factory parent, its associations lose the anchor to the instance.
I know that I can just do

FactoryBot.define do
  factory :post do
    user
    
    factory :approved_post
  end
end

But I prefer to keep my factories in separated files for different models.
I think this feature might not work with associations as expected.

Reproduction Steps

class Post < ApplicationRecord
end

class ApprovedPost < Post
  self.table_name = 'approved_posts'
end

FactoryBot.define do
  factory :post do
    user
  end
end

FactoryBot.define do
  factory :approved_post, parent: :post
end

>> include FactoryBot::Syntax::Methods
>> post = create(:post)
>> approved_post = create(:approved_post)

Expected behavior

>> post.user.post == post
=> true
>> approved_post.user.approved_post == post
=> true

Actual behavior

>> post.user.post == post
=> true
>> approved_post.user.approved_post == post
=> false

System configuration

factory_bot (6.2.0):
rails (6.1.7.6):
ruby '2.7.5':

[Alex Kuhn]

It inherits the parent class, so I just defined it with class: 'ApprovedPost' and it solves the problem.