Questions saved in private collections has access to revoked database

Hi, I can see the following behaviour.

  1. We grant user access to the database
  2. The user saved some questions to he's or she's private collection
  3. We revoke this user access to the database.

Expected behaviour: The user no longer can access those questions
Actual behaviour: The user can access those questions but can't modify

Is it possible to remove access altogether?

More info: In our instance, we don't have shared collections, so the only place user can safe their questions is the private user's collection.

What would be advice or actions to achieve our wanted behaviour?

Thank you!