Hello!
We (my mother and I) have raised these little terrors all my life... over 35yrs and all I can tell you is that you probaly won't get this behavior to stop. I have seen them have the strangest little habits.
I have a one about the same age as yours and he is terrified of my husband. Have no idea why; we have all kinds of animals and they all love my husband.
Possum (my yorkie) loves him in the morning when he first wakes up but as soon as he puts his boots on... that's it.
Possum will pee himself if my husband moves too fast. Its a little comical.
But Possum loves our son, who is my husband made over. Possum is fine with my son's boots.
Your baby is just being a yorkie. As long as she isn't biting I would just ignore it.
Good Luck!