Yeah, it's like trying to use an ORM to find data in the database that's invalid due to a bug. You can't see things in the system that break the premises of the system by using the system, and the fact that some things are "supposed to be impossible" doesn't change the reality of what's actually occurring in the data store.

So customer support needs to know how the systems works and need to understand what the data means, but also has to know when the system is factually incorrect. Customer support has to know when the second party is speaking the truth.