I'm in my 30's now and wondering this lately. My Mum was the NRP (for reasons to do with her career) and I think I didn't feel as safe and secure with her at some points.
When I was a toddler, we were on holiday and I for a joke she hid where I couldn't see her when I turned to look at something. I panicked and ran back off the street to the holiday home. It was probably only a minute or two, she snapped a few photos of me looking for her, but I remember being so scared.
Another time I remember begging her to stop scaring me at night after a scary film. It was again meant to be a joke but went on a little too far and I can just remember being so scared and feeling far away from my home.
She would have been utterly mortified to know she scared me and was great and supportive in lots of other ways.
I am wondering though if children are generally more sensitives to getting scared like this when spending time with non resident parents? Because there is less security maybe?