The problem isn't so much about the correctness of a record, or being able to recover from changes in state, it's more about ensuring the consistency of the states of multiple different parts of the overall system. How do you recover consistency?

Even our brains have not entirely solved this problem. Sometimes when you hear a stimulus such as a phone ringing different parts of your brain will receive and process the stimulus at different times, so it can seem as though you become conscious that the phone has rung before you become consciously aware of hearing the sound of it ringing.

In a computer system you might have some parts working based on derived values from a record in the source of truth. This can lead to other parts working based on other derived values based on a different value when it has changed, so they disagree.