Here we go again.
Ostap, you know when and how the past perfect is used. You also know that native speakers are not too dogmatic about 'rules' with the past perfect/past simple.
You will get the same answers you always get when you raise this question in one form or another. Some will make you happy, some not. In either case, you will ask a couple of extra questions to 'confirm' you have understood.
I really don't see the point in this.
Student or Learner