The problem is really that many formal proofs of consensus have focused only on the network fault model, and neglected the storage fault model.
Both network/storage fault models require practical engineering efforts to get right. I think a better term for this is “near-Byzantine” fault tolerance. It's what non-Byzantine fault tolerance looks like when implemented correctly in the real world—the GP comment is a great example of how to approach and think about this from an engineering perspective.
I dive into this in detail also here: https://www.youtube.com/watch?v=rNmZZLant9o