I’ve noticed that I do this too. Especially when meeting new people, like all the other parents I’ve been meeting either at birthday parties or something. For me it comes from social anxiety, and being a little over stimulated from meeting some one new. I’m otherwise alone quite a bit. After while I realize I’ve been so focused on paying attention to this other person, working hard to be my best version of me, and also working hard to make enough eye contact and think before I speak, etc, that I realize I’ve lost tract of my child and what they are doing, usually getting injured off to the side.