An old message can contradict the explanation you eventually gave yourself.

You build an account of what happened, and it hardens, and then something written at the time contradicts it. The message shows you were warmer than you remember, or more angry, or that you knew something you later decided you did not. It is uncomfortable because the explanation had become part of how you understand yourself.

When the record disagrees with the story, resist deciding immediately which is right. Both the message and the memory are partial. What is worth asking is why the version you built was the one you needed.