I can relate a little bit. I used to have moments where my arms and legs went in the air. When I googled it, it was suggested that it’s related to the baby startle reflex. It’s stopped happening to me now, but sometimes my arms still jerk a bit. The answers I found were in an article about late onset Tourette’s. I’m not suggesting you have that. But one possibility is that your experience has a similarity. For me, I figured that when I was a baby I felt unsafe, possibly was startled (in a way that was akin to trauma).