It happens to me too. I don’t think I dissociate as such, but it feels a bit like a sensory overload, like I’ve taken in too much and my brain is struggling to process. I make notes of everything that I remember immediately afterwards, but sometimes it takes a day or two for other details to come through. Sometimes I go to sleep and as my mind relaxes, new details from the session emerge and I quickly jot them on my phone. I tend to properly journal about the sessions a couple of days after, just so that I give my brain enough time to process and remember things.