Has anyone seen this before?
This, I believe, is an imaginary friend gone wrong. I noticed it when I first loaded my game after the latest patch though I don't know for sure if that was what caused it. The teen had just aged up before the save. When I first opened the game, her friendship panel was fine. Then I noticed this. If i kept going, I eventually lost control - her pic would display only though I was switching to other sims. It was a mess. I have solved it (hopes) by going back to an earlier save before she grew up. I have also put her's and her brother's dolls in her mother's inventory and hope that it won't happen again. The dolls were cute for the first five minutes but I like my sims to learn some skills.
By the way, her mother is very ugly.