My sister was holding my DD, and she was perfectly happy. Then she managed to knock a soda over where she was sitting with my sister and got it on her clothes. I jokingly told my sister "Nope! You didn't move your soda far enough so you change her!"
I gave her the clothes, and she laid DD down. Once she unbuttoned the first button of her pjs, dd let out a terrified scream. She didn't stop until my sister had changed her, even though I sat right next to her. It was a super quick change, then I grabbed her. She was very upset, but calmed down right away in my arms.
My sister has NEVER hurt dd. She's an amazing aunt and loves dd. Dd does, however, go to a sitters some days during the week. Does it sound like maybe something happened at the sitters? Dd went from smiling when she saw her sitter to just a blank stare. The cries have come back as well when I leave.