K.C.
Have you ever read the book, Nanny Diaries ( I know it was a terrible movie too!)
In the book ( I am loosely quoting) the "nanny" said that she had to be a very good nanny. And in order to do that she needs to make the child like her enough, but not too much because then the mom wouldn't like her. It's a tough thing for a mom to watch a relationship between the "hired help" and her child. Maybe when she is home, she wants to really have one on one time with her little one. Moms can be jealous too!
I would just take a deep breath and let this one go. The child knows you care and that is the only thing that matters.
K.