Items disappear

Since the last update, every time I go from one save screen to another, everything in my inventories disappears, both my Sims’ and the household inventory. It started with homework books going missing, then I noticed all my bookcases and nectar racks were empty too. Now, when I try to buy more homework books and hand them out, they just get stuck in my hand. And if I tell a Sim to grab a book from a shelf, they freeze up and glitch. Those new books then go and also disappear.