After the patch, some of my sims disappeared from game. I removed my mods folder and every stitch of CC. Started a new game folder and fixed my sim in CAS so they were reset from all CC, and they still didn't show up in game. Other people reported this problem and then some genius narrowed it down to one problem. Any sim who has the Father Winter child trait disappears. Upon hearing this, I realized as well the sims that disappeared from game had this trait.