My boyfriends daughter worries me

My boyfriends daughter will be three in March. And the way she plays with her dolls has me worried.

Today she put all of them face down and put the blanket over them and started spanking them saying "Go to sleep!!" Then she grabbed one of the dolls and looks at it "face to face" then says "Stop!" And spanks it then put her dolls face against hers and says "did you hear me? Stop!" And smacks the dolls face.

When she's with us, we never have to really discipline her in this way. Do you think she's being abused at her mom's and reflecting it on her dolls?