Sims 4 - Some Sims Are Completely Black (Even Hair And Clothes)

So here's something I've never experienced before. At least two random sims in my game suddenly turned completely black for reasons I am unable to discern, and now appear as silhouetted outlines. Reflective maps on these sims are still visible, their eyes, hair, buttons on clothes still shine. But apart from that, these sims are completely shadowed, clothes and all.

I have all current DLC for the Sims 4, and I have plenty of CC, but never before have I encountered something such as this.