the only times that has happened to me is when I have disassociated due to the discussion of a very painful topic. T knew I was in pain and showed little emotion but I still answered question appropriately. She never realized I had disassociated. I didn't realize it happened until I walked out of her office and got in my car. It was like I woke up. So I contacted to figure out what happened. She said that itth sounded like I had disassociated and she wished I had told her in session so that we could work on it. I didn't say anything as I didn't know what was going on but it gave her a better idea what to look for.