I think this would be a great thing to share with your new T. Even if you don't want to share the earlier diagnosis, talking about the times you are checking out in session can help you identify how often you do it and what seems to trigger it.

I understand your concern that you are missing things because of it, though. For what it's worth, I have talked with my T about that as well and he has sort of encouraged me to roll with it. I check out when I need to, and even when I can't re,ember what's going on in a session, it's impacting me and helping me move gradually towards change. I've started to think of T as an accumulation of experiences rather than discrete sessions or things that I have learned.