Solved
Cakes Disappear When Moved
After the most recent update, when I cook a birthday cake, when it is finished my Sim will put it somewhere. However, to be able to put candles on it, it has to be in the center of a table or counter, which means it always has to be moved. As soon as I try to move the cake, it completely disappears. There's a movement square like I am dragging and placing and object, but the cake is gone and once it is "placed" it's still gone and I can't select it.
As such, I can't naturally age-up my Sims.
Confirmed this on a new save with no mods.
I ran the "Verify Integry of Game Files" process in Steam and it reacquired some files, which fixed the issue!
