The problem you're referring to is how BD encryption keys are rotated as they are compromised. When a player gets reversed and the keys dumped, the organization basically revokes those keys for any new discs going forward. Practically, this means that things like when your particular BD was pressed matter for what keys you need. It's a pain in the ass; deCSS was much nicer.

e: apparently since I last used it makemkv now finds as many of these on its own as it can: https://www.makemkv.com/svq/