Maybe she was always like that or like that with everyone and your just noticing it now?
She reminds me a lot of a fellow mom I have to deal with. Shes like that with everyone, but to a lesser more socially acceptable extent. This woman actually texts me "call me now" or "why did you not tell me the kids were supposed to bring x to this event. I need you to tell me because im busy"...umm??? Cause youre an adult and we both receive the same emails? This mom was a walkaway and for some crazy reason she has an ex fawning over her and new boyfriends buying her stuff etc.
Like i said, she sounds like a incompetent control freak. I wouldnt worry about the whys, maybe just how to deal with her. How to establish boundaries with soneone trying to walk all over you amd most likely everyone else.