I noticed the other day when one person in my chat list IM's me in Gmail, I don't get a desktop notification and all chats with him are not logged. At first I wondered if he was just off the record, but he couldn't seem to find anything that would be blocking me. We can still chat with each other, it just doesn't log the conversations.
His chats with other people and my chats with other people are saved. Does anyone know what setting we need to set in order to get chats between the two of us to be saved? We haven't (knowingly) blocked each other.